ARVO 2015 Annual Meeting Abstracts
244 Cataract surgery: Optimisation of outcomes
Monday, May 04, 2015 11:00 AM–12:45 PM
Exhibit Hall Poster Session
Program #/Board # Range: 1895–1927/C0203–C0235
Organizing Section: Lens
Contributing Section(s): Physiology/Pharmacology
Program Number: 1895 Poster Board Number: C0203
Presentation Time: 11:00 AM–12:45 PM
Comparison of ocular biometry and intraocular lens power
using dual Scheimpflug analyzer and optical low-coherence
reflectometry
Kyung Eun Han, Hyo Kyung Lee, Minchul Shin. Ophthalmology,
Chuncheon Sacred Heart Hospital, Chuncheon, Korea (the Republic
of).
Purpose: Recently, dual Scheimpflug analyzer (DSA) which could
measure axial length and calculate intraocular lens (IOL) power were
developed. However, the optical biometry and IOL power were not
compared with the previous optical biometry device such as optical
low-coherence reflectometry (OLCR). This study was conducted
to compare ocular biometry and IOL power obtained by DSA and
OLCR in patients with cataract.
Methods: Sixty-nine cataractous eyes of 51 subjects were evaluated
with DSA (Galilei G6™; Ziemer, Port, Switzerland) and OLCR
(Lenstar®; Haag-Streit, Koeniz, Switzerland). Mean keratometry (K),
axial length (AL), anterior chamber depth (ACD), lens thickness
(LT), white-to-white (WTW) and IOL power calculated using the
SRK/T formula were obtained with each device. Ocular biometry and
calculated IOL power were compared with paired t-test. Correlations
of the measurements were evaluated with Pearson correlation test.
And, agreements of the measurements were analyzed with BlandAltman plot.
Results: Mean K, AL, and IOL power showed no statistically
significant differences between the two devices (all p values >
0.05). However, ACD, LT and WTW showed statistically significant
differences between the two devices (p < 0.001, p < 0.001, p = 0.001,
respectively). Except for the WTW (r = 0.70, p < 0.001), mean K,
AL, ACD, LT and IOL power showed very high correlations with
each other (all r > 0.80, all p values < 0.001). The 95% limits of
agreements of mean K, AL, ACD, LT, WTW, and IOL power were
2.87 diopter (D), 0.59 mm, 1.00 mm, 1.29 mm, 3.41 mm, 1.36 D,
respectively.
Conclusions: Although highly correlated, DSA and OLCR systems
cannot be used interchangeably for optical biometry and IOL power
in patients with cataract.
Commercial Relationships: Kyung Eun Han, None; Hyo Kyung
Lee, None; Minchul Shin, None
Program Number: 1896 Poster Board Number: C0204
Presentation Time: 11:00 AM–12:45 PM
Two models for post-op IOL Position calculation with a new ocular
biometer device
Diana Bogusevschi1, Andrew Nolan1, Arthur Cummings2, 1, Maria
Galligan1, Michael C. Mrochen1, 3. 1ClearSight Innovations ldt.,
Dublin, Ireland; 2Wellington Eye Clinic, Dublin, Ireland; 3IROC
Science, Zurich, Switzerland.
Purpose: Two new post-op Anterior Chamber Depth (ACD)
prediction calculation models have been developed. A retrospective
data analysis of cataract patients, measured on Lenstar LS900, HaagStreit, was devised to investigate the position prediction accuracy of
the new models. The accuracy of the two models is also assessed for
a separate clinical study of a novel ocular measurement device.
Methods: For the retrospective data analysis, a total of 306 eyes
scheduled for cataract surgery, have been measured preoperatively
and postoperatively at 4-8 weeks by means of a standard-of-care
(SOC) ocular biometer (Lenstar LS900, Haag-Streit). Two new
prediction models (Model A and B) for post-op IOL position, have
been developed. For both models, the raw data of the SOC device
were used to obtain true optical path properties and multi-regression
analysis with preoperative clinical factors was performed to derive
Models A and B.
Model A depends on the pre-op ACD, Crystalline Lens Thickness
(LT) and IOL Thickness variables and Model B depends on the preop ACD, LT, IOL Thickness, WTW, Gender and Anterior Corneal
Axis.
Models A and B have been tested on a second prospective cataract
patients study, where a new ocular biometry system that consists
of a Purkinje imaging method and an optical coherence device was
used to measure the ocular parameters for IOL power calculation.
The post-op ACD measured with the new device and the calculated
predicted ACD values are compared with the corrected Lenstar
measured ACD parameters.
Results: In the retrospective data analysis, the Model A mean
position error between the ACD optical path and predicted IOL
position was 0.1mm ±0.07mm for monofocal IOL’s. The Model B
mean position error was 0.09 ±0.07 mm. No statistical significant
difference was found between the measured and calculated means for
both models (p = 0.1; paired t-test).
The eyes measured on the new ocular biometer have shown a
mean position error of 0.13 ±0.03 mm for Model A (p = 0.2; paired
t-test) and 0.17 ±0.04 mm for Model B (p = 0.3; paired t-test). The
difference between the post-op ACD measured on the two devices is
0.1±0.03mm (p = 0.54; paired t-test).
Conclusions: Two new ACD prediction models have been shown to
deliver good prediction results compared with the existing Lenstar
LS900. The models also provide the basis for accurate IOL power
calculation with a new ocular biometer.
Commercial Relationships: Diana Bogusevschi, ClearSight
Innovations ltd (E), ClearSight Innovations ltd (I); Andrew Nolan,
ClearSight Innovations ltd (E), ClearSight Innovations ltd (I); Arthur
Cummings, ClearSight Innovations ltd (C), ClearSight Innovations
ltd (I), Wellington Eye Clinic (E); Maria Galligan, ClearSight
Innovations ltd (E), ClearSight Innovations ltd (I); Michael C.
Mrochen, ClearSight Innovations ltd (E), ClearSight Innovations ltd
(I)
Clinical Trial: CIV-IE-13-12-011775
Program Number: 1897 Poster Board Number: C0205
Presentation Time: 11:00 AM–12:45 PM
Fluidic Dynamics of Intraocular Pressure (IOP) as it Applies
to Gravity-Fed versus Actively-Controlled Phacoemulsification
Systems
Ramon C. Dimalanta1, Kevin Miller3, Manuel Nicoli2. 1Global
Medical Affairs, Alcon, Lake Forest, CA; 2Instituto Oftalmos, Buenos
Aires, Argentina; 3Stein Eye Institute, UCLA, Los Angeles, CA.
Purpose: To use fundamental fluid dynamic theory to explain and
compare the performance of 3 phacoemulsification fluidic systems in
terms of their ability to maintain a target IOP under varying aspiration
flow rates.
Methods: The hand piece of each machine was inserted into a small,
rigid test chamber fitted with access ports for pressure measurement.
The machines were operated in a traditional gravity fed irrigation
mode with bottles of balanced salt solution hanging from an
adjustable pole. One machine was operated in an active control mode.
Another machine was operated using pressurized air to augment the
©2015, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
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ARVO 2015 Annual Meeting Abstracts
pressure within the hanging bottle. Bottle heights and/or bottle/bag
pressures were selected to provide equal starting target pressures at
zero aspiration flow. Aspiration flow rates were then adjusted across
their respective ranges while steady state pressures were measured in
the test chamber.
Results: For all gravity fed systems, measured IOP decreased with
increasing aspiration flow regardless of bottle height or starting
IOP; following Bernoulli’s equation. This included the system with
pressurized infusion. The system with active fluidics maintained
the target IOP at all flow rates (within 0.02 mmHg per cc/min),
but experienced a slight decrease in IOP at the highest flow rate
(maximum drop = 6.0 mmHg).
Conclusions: Guided by classic fluid mechanic fundamentals
of inviscid fluids, laboratory experiments demonstrated that at
equivalent target IOPs, all gravity fed systems, including the one with
pressurized infusion, experienced a decrease in IOP as a function of
increasing aspiration flow. The system with active fluidics provided
a constant steady state IOP across all but the very highest flow rates
under test.
Commercial Relationships: Ramon C. Dimalanta, Alcon
Laboratories (E), Alcon Laboratories (E); Kevin Miller, Alcon
Laboratories (C); Manuel Nicoli, None
Program Number: 1898 Poster Board Number: C0206
Presentation Time: 11:00 AM–12:45 PM
Numerical simulations of flow and mass transport processes in
the anterior chamber in the presence of an iris-fixated intraocular
lens
Rodolfo Repetto1, Peyman Davvalo Khongar1, Jan O. Pralits1,
Jennifer H. Siggers2, Paolo Soleri3. 1Department of Civil, Chemical
and Environmental engineering, University of Genoa, Genoa, Italy;
2
Department of Bioengineering, Imperial College London, London,
United Kingdom; 3Ophtec BV, Groningen, Netherlands.
Purpose: In this study we investigated how implantation of
iris-fixated intraocular lenses (IOLs) affects aqueous humor
flow characteristics and mass transport processes in the anterior
chamber. Specifically, we studied changes in the wall shear stress
distribution and oxygen/nutrient availability on the cornea, after lens
implantation.
Methods: We adopted a mathematical model to study aqueous
flow and oxygen/nutrient concentration distribution in the anterior
chamber in the presence of an iris-fixated IOL. Numerical solutions
on idealized but realistic geometries were obtained employing the
open source software OpenFOAM. The validity of the numerical
results were confirmed by analytical solutions obtained through a
simplified model based on the lubrication theory. We considered
various mechanisms that generate aqueous flow in the anterior
chamber and focused, in particular, on the production/drainage flow
and the thermal flow generated by a temperature gradient across the
anterior chamber.
Results: The model provides a detailed description of the velocity,
pressure and concentration distribution in the anterior chamber, both
in the presence and absence of the IOL. Results show that changes
in fluid pressure after implantation of the IOL are negligible. Wall
shear stress distribution and mass transport processes in the anterior
chamber are significantly modified by the presence of the IOL.
However, the maximum wall shear stress on the cornea does not grow
after IOL implantation.
Conclusions: The study sheds some light on the changes induced by
implantation of an iris-fixated IOL on fluid flow and mass transport in
the anterior chamber, an information that would be difficult to obtain
without making use of a mathematical model. Results suggest that
changes in the wall shear stress, albeit significant, are unlikely to be
the cause of the complications associated with the use of iris-fixated
IOLs.
Commercial Relationships: Rodolfo Repetto, Ophtec BV (F);
Peyman Davvalo Khongar, None; Jan O. Pralits, Ophtec BV (F);
Jennifer H. Siggers, Ophtec BV (F); Paolo Soleri, Ophtec BV (E)
Program Number: 1899 Poster Board Number: C0207
Presentation Time: 11:00 AM–12:45 PM
Evaluation of a New Compact Phacoemulsification System for
Extracapsular Lens Extraction during Cataract Surgery in a
Rabbit Model
Ling C. Huang1, Mercedes Salvador-Silva1, Tim Hunter2, Arlene
Gwon3. 1R&D - Biological Sciences, Abbott Medical Optics, Santa
Ana, CA; 2R&D - Surgical Equipment, Abbott Medical Optics, Santa
Ana, CA; 3Ophthalmology, University of California Irvine, Irvine,
CA.
Purpose: To evaluate performance and acceptability of a new
compact phacoemulsification system for extracapsular lens extraction
during cataract surgery in a rabbit model.
Methods: Extracapsular lens extraction was performed in 6 New
Zealand white rabbits (~12 months old) with grade 2-3 cataracts.
Four eyes of 2 rabbits were used to evaluate fluidics (irrigation/
aspiration) performance and cutting efficiency of the new
phacoemulsification (phaco) system using the Ellips® FX handpiece
and WhiteStar® handpiece. Diathermy defined as power required
per instrument (pencil and forceps probe) was examined. Eight eyes
of 4 rabbits were used to evaluate energy requirement and fluidics
performance. Ocular biocompatibility of the new phaco fluidics pack
was assessed by slit-lamp biomicroscopy for 4 weeks following
surgery and compared to postoperative results obtained in the
contralateral eye with a currently marketed compact phaco system
and associated fluidics pack.
Results: Fluidics performance of the new phaco system was
acceptable with no surge or bounce at the maximum vacuum range
of 200-600 mmHg and flow rate of 20-40 cc/min in Peristaltic pump
mode. The new system was more effective in cutting using the
Ellips® FX handpiece (score 3.0+0.6) compared to the WhiteStar®
handpiece (score 2.1+0.7, p<0.05). For a grade 2 cataract in the
rabbit model, the effective phaco time (EPT) was ~1 minute and 11
seconds, and ultrasonic time (UST) was ~32.6 seconds. For a grade
3 cataract, the EPT was ~2 minute and 14 seconds, and the UST was
~2 minutes and 42 seconds. Optimal power setting of the new system
was determined to be 20% for cauterizing tissue with pencil probe
and between 20-40% using the forceps probe. No post-operative
complications and no differences in slit-lamp findings (scores 0-2,
p<0.05) were observed in eyes treated with either the new or control
phaco fluidics pack.
Conclusions: Results from this study demonstrated advantages of
using the new phaco system with Ellips® FX handpiece and pencil
probes for improved phaco power, enhanced fluidics performance
and reduced operative duration during extracapsular lens extraction
in cataract surgery. EPT and UST were clinically appropriate
and acceptable for both grade 2 & 3 cataract in a rabbit model.
Unequivocal surgical outcomes also confirmed biocompatibility of
the new phaco fluidics pack.
Commercial Relationships: Ling C. Huang, Abbott Medical Optics
(E); Mercedes Salvador-Silva, Abbott Medical Optics (E); Tim
Hunter, Abbott Medical Optics (E); Arlene Gwon, Abbott Medical
Optics (C)
©2015, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
to reproduce any abstract, contact the ARVO Office at pubs@arvo.org.
ARVO 2015 Annual Meeting Abstracts
Program Number: 1900 Poster Board Number: C0208
Presentation Time: 11:00 AM–12:45 PM
Prevalence and Incidence of Cataracts in a Population of Yucatan
Miniswines after Induction of Type I Diabetes: a Model for
Preventative or Therapeutic Cataract Therapies
Alain Stricker-Krongrad1, Chris Hanks1, Melissa Freeman1, Sarah
Schlink1, Lauren Delaney1, Jason Liu1, Armando T. Cruz2, Joan
Wicks2, Serge Rousselle2, Guy Bouchard1. 1Sinclair Research Center,
L.L.C., Columbia, MO; 2Alizee Pathology, LLC, Thurmont, MD.
Purpose: Cataracts as a consequence of chronic diabetes is
considered a leading cause of legal blindness in humans in the United
States and is also observed frequently in aged diabetic populations
(>65%).
Assess post-induction (PI) onset of clinical ocular cataract(s) in
a colony of over 266 castrated, male, diabetic, Yucatan miniature
swine.
Methods: Diabetic miniature swine were routinely screened by
a veterinarian for clinical ocular abnormalities including visible
‘mature’ cataracts.
Results: Over the course of a 6 month period, the prevalence was
30% (80 positive animals out of 266 animals). The most recent
incidence (past 2.5 months) was 20.4% (38 positive animals with
60 affected eyes from pool of 186 previously negative animals).
Eighteen animals had bilateral and 20 animals had unilateral cataracts
(OD: 31; OS: 29). Cataract onset ranged from 2 to 19 months PI
with an average of 11 months PI. Cataracts were detected earlier
in animals when euglycaemia was intentionally less controlled,
which supports the current predominant theory of glycation–induced
cataract development. Interestingly, swine unlike human are not
capable of glycating their hemoglobin due to the lack of penetration
of glucose into the red cells. Miniswine with cataracts appear to
function acceptably well despite the assumed visual handicap by
relying on other senses.
Conclusions: Diabetic Yucatan miniature swine commonly manifest
with cataracts on average at 11 months post-induction. Insulin
regimen and glucose control are strong factors in the prevalence and
incidence of cataracts in diabetic miniswines. Our data also suggests
that the glycation of swine lenses readily occurs due to the high
incidence of cataracts in diabetic animals with non-optimal glucose
control. In addition the diabetic miniswine would provide a good
model for preventative or therapeutic cataract therapies.
Diabetic Yucatan Miniswine, Saggital Section of Pathological Lens
with Cataractous Nuclear and Cortical Area.
Diabetic Yucatan Cataract Lens Detail.
*Solid arrowheads=bladder cells (hydropic degeneration of lens fiber
cells)
*Arrows=Morgagnian globules (bright pink aggregates of denatured
lens protein)
*Double arrow=fibroblastic metaplasia of the anterior lens epithelium
*Clear arrowhead=slight reactive hyperplasia of the lens epithelium
©2015, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
to reproduce any abstract, contact the ARVO Office at pubs@arvo.org.
ARVO 2015 Annual Meeting Abstracts
Commercial Relationships: Alain Stricker-Krongrad, None;
Chris Hanks, None; Melissa Freeman, None; Sarah Schlink,
None; Lauren Delaney, None; Jason Liu, None; Armando T. Cruz,
None; Joan Wicks, None; Serge Rousselle, None; Guy Bouchard,
None
Program Number: 1901 Poster Board Number: C0209
Presentation Time: 11:00 AM–12:45 PM
Trypan Blue as a Surgical Adjunct to Decrease Lens Capsule
Elasticity in Pediatric Cataract Surgery
Allison E. Rizzuti1, Gabrielle Fridman1, Mark Rolain2, Stephen
C. Kaufman1. 1Ophthalmology, SUNY Downstate, Brooklyn, NY;
2
Ophthalmology, Beaumont Hospital, Royal Oak, MI.
Purpose: The increased elasticity of the lens capsule in children
complicates the successful completion of the continuous curvilinear
capsulorhexis (CCC) during pediatric cataract surgery. Trypan blue
reduces the elasticity of the lens capsule, possibly facilitating the
creation of the CCC in pediatric patients. We investigated the effects
of trypan blue on ease of completion of capsulorhexis, lens capsule
elasticity and intralenticular pressure.
Methods: 24 lenses were excised from fresh sheep whole globes.
12 lenses were immersed in trypan blue for 2.5 minutes and 12
lenses were immersed in BSS for 2.5 minutes. Ease of completion
of capsulorhexis was assessed using our grading system (1=difficult,
4=undemanding), and intralenticular pressure was quantified using a
Schiotz Tonometer.
Results: Lenses immersed in trypan blue averaged a score of 2.58
out of 4. Capsulorhexis was successfully completed in 91.7%. Lenses
immersed in BSS averaged a score of 1.5 out of 4 (p = 0.031) with
a success rate of 58.3%. Immersion in tyrpan blue decreased the
intralenticular pressure by an average of 4.5mmHg (p = 0.025).
Conclusions: Our data confirmed that the graded ease of completing
a continuous curvilinear capsulorhexis was significantly improved
with trypan blue, not only by allowing the surgeon to distinguish
the lens capsule, but also by decreasing lens capsule elasticity.
Additionally, intralenticular pressure was significantly decreased
possibly due to the osmotic effect of the dye.
Completed continuous curvilinear capsulorhexis on a sheep lens that
had been immersed in trypan blue.
Ease of capsulorhexis with and without the use of capsule staining
with trypan blue on a four-point scale, The shorter the bar, the greater
the difficulty: 1 (difficult) to 4 (undemanding).
Commercial Relationships: Allison E. Rizzuti, None; Gabrielle
Fridman, None; Mark Rolain, None; Stephen C. Kaufman, None
Program Number: 1902 Poster Board Number: C0210
Presentation Time: 11:00 AM–12:45 PM
Adaptation of Micro Vibration Motors from Cell Phones to
Corneal Incisions
Samuel Werner1, Adam Pigg2, Victor Sargent2. 1Ophthalmology and
Vision Science, University of Arizona Ophthalmology Residency,
Anchorage, AK; 2Mechanical Engineering, University of Alaska,
Anchorage, Anchorage, AK.
Purpose: Previous studies have shown that corneal incision
architecture is significant in allowing wounds to self-seal and prevent
operative complications. Ultra compact micro vibration motors
(MVM) that are ubiquitous in cell phones and other devices can
be easily fitted to surgical instruments to provide new modalities
in cutting. We designed a device that attaches to microsurgical
instruments and generates planar blade oscillations with the goal of
improving broad corneal incisions similar to those created during
manual small-incision cataract surgery. In this project we analyzed
the force required to initiate and maintain an incision as well as
incision appearance to determine the effect of outfitting blades with
the MVM attachment.
©2015, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
to reproduce any abstract, contact the ARVO Office at pubs@arvo.org.
ARVO 2015 Annual Meeting Abstracts
Methods: Ballistic gelatin was used as a tissue analog. The analog
was placed into a sample holder outfitted with two Omega strain
gauges. The testing frame was fitted with a stepper motor that
moved a #5 Beaver blade along a manufactured rail system. Voltage
across the strain gage circuit was measured using an oscilloscope.
From these measurements, forces required to initiate and maintain
an incision were calculated for blades outfitted with the MVM
attachment and compared to control blades without the MVM
attachment. Once incisions were completed, wound architecture was
examined using light microscopy at 80x magnification.
Results: The force required to initiate incisions with the MVM
attachment was close to 2.3N compared to 3.5N without vibration.
The force exerted during the steady loading portion of the incision
was lower with blades fitted with the MVM attachment than those
without, indicating that once the incision had been initiated it was
easier to maintain. Appearance of ballistic gelatin samples under light
microscopy revealed smoother incision margins with vibrating blades
than those without.
Conclusions: Outfitting blades with the MVM attachment reduces
the force required to initiate and maintain an incision, reducing
tissue tension and improving wound appearance. If these results
were confirmed with further testing on cornea tissue and more indepth wound analysis, these findings would suggest a possible role
for MVM attachments in improving corneal incision formation and
architecture.
posterior corneal surface. We prospectively evaluated the accuracy
of total corneal astigmatism measurements with a novel specular
reflection technique.
Methods: Refractive astigmatism was measured with autorefraction
(ARK-530A, Nidek) in 24 eyes of 24 patients with a monofocal,
non-toric IOL (Acrysof SA60AT, Alcon). Alignment errors of the
IOL were assumed to be negligible; thus, refractive astigmatism
was assumed to consist entirely of anterior and posterior corneal
astigmatism. Anterior and posterior corneal curvatures were
measured with a specular reflection technique (Cassini, i-Optics).
Subsequently, corneal astigmatism was calculated based on only the
anterior curvatures as well as based on both anterior and posterior
curvatures. Measurement error of either approach was defined as the
absolute difference with autorefraction. Reduction of measurement
error if the calculation included posterior corneal curvatures was
tested for statistical significance using the paired-samples T test.
Results: The mean measurement error of cylinder magnitude was
0.29 ± 0.21 D and 0.27 ± 0.20 D if the measurement excluded and
included posterior curvatures, respectively. The mean measurement
error of cylinder axis was 26.6 ± 38.7 degrees and 22.3 ± 38.5
degrees if the measurement excluded and included posterior
curvatures, respectively. The reduction in measurement error of
cylinder magnitude was not statistically significant (P=0.60).
However, the reduction in measurement error of cylinder axis was
statistically significant (P<0.01).
Conclusions: We presented a novel specular reflection technique
that enables measurement of total corneal astigmatism. Compared to
measurements of only anterior corneal curvatures, the measurement
error of cylinder axis was statistically significantly reduced by
4.3 degrees if posterior curvatures were included. This may be
particularly advantageous in the planning of toric IOL implantation.
Force versus time plot. No load from 0-2 seconds. Blade impact
occurs at roughly 3 seconds. Breakthrough and incision propagation
occurs at the sudden change in voltage between 6 and 8 seconds.
Commercial Relationships: Samuel Werner, Provisional Patent
Application No. 61/892,199, entitled “Surgical Cutting Device and
Methods of Using Same,” (P); Adam Pigg, None; Victor Sargent,
None
Program Number: 1903 Poster Board Number: C0211
Presentation Time: 11:00 AM–12:45 PM
Accuracy of a novel specular reflection technique for
measurement of total corneal astigmatism
Stijn Klijn1, Nicolaas J. Reus2, 1, Charlotte M. van der Sommen1,
Victor Arni D. Sicam1. 1Rotterdam Ophthalmic Institute, Rotterdam,
Netherlands; 2Department of Ophthalmology, Amphia Hospital,
Breda, Netherlands.
Purpose: Measurements of corneal astigmatism have traditionally
been based on information of only the anterior corneal surface.
Accurate planning of toric intraocular lens (IOL) implantation
requires knowledge on total corneal astigmatism, which includes the
Reduction of measurement error of corneal cylinder magnitude (blue)
and axis (green) in each eye if anterior and posterior instead of only
anterior corneal curvatures are measured with specular reflections.
One unit equals 0.02 D or 1 degree.
Commercial Relationships: Stijn Klijn, None; Nicolaas J. Reus,
i-Optics (C); Charlotte M. van der Sommen, None; Victor Arni D.
Sicam, i-Optics (E), i-Optics (P)
Support: Nuts OHRA, Stichting Achmea Gezondheidszorg,
Stichting Coolsingel
©2015, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
to reproduce any abstract, contact the ARVO Office at pubs@arvo.org.
ARVO 2015 Annual Meeting Abstracts
Program Number: 1904 Poster Board Number: C0212
Presentation Time: 11:00 AM–12:45 PM
Estimation Errors for Total Corneal Astigmatism Using
Keratomatric Astigmatism in Patients before Cataract Surgery
Tianyu Zheng, Yi Lu. Ophthalmology, EYE and ENT Hosp of Fudan
Univ, Shanghai, China.
Purpose: Since more and more people are willing to correct corneal
astigmatism during cataract surgery, the accuracy of preoperative
estimation of corneal astigmatism is becoming increasingly
important. Previous studies found the widely used keratomaric
method could lead to significant estimation errors for total corneal
astigmatism. However, in previous studies, the part of elder subjects
was relatively limited. This study focused on the elder patients
preparing for age-related cataract surgery, to evaluate the estimation
errors for total corneal astigmatism using keratometric astigmatism
(KA).
Methods: A prospective, observational study.374 eyes of 374 patients
(45 to 84 years) preparing for cataract surgery were measured with
Pentacam. KA was obtained using the anterior corneal surface
measurement and the keratometric index while neglecting the
posterior corneal surface measurement. The Pentacam-derived total
corneal astigmatism (PA) was derived by vector analysis of the
astigmatism on both corneal surfaces.
Results: The magnitude of anterior and posterior corneal astigmatism
was 0.99 ± 0.71 D and 0.25 ± 0.14 D respectively. Posterior corneal
astigmatism decreased with age. The mean magnitude was 0.89 ±
0.63 D for KA and 0.97 ± 0.69 D for PA. The absolute error of the
magnitude (EM) and angle (EA) between PA and KA were 0.18 ±
0.14 D and 7.7 ± 11.0 degree. The magnitude of the error vector (EV)
was 0.24 ± 0.14 D. 19 eyes (5.1%) had an EV larger than 0.5 D. KA
overestimated total corneal astigmatism in eyes with with-the-rule
anterior astigmatism, and underestimated that in the others. EM was
significantly larger in eyes with against-the-rule anterior astigmatism,
but EA was larger in eyes with with-the-rule and oblique anterior
astigmatism. In eyes with KA larger than 2 D, or elder than 65 years,
there was a remarkable increase in EM. And EM was higher in eyes
with axial length of 20 to 24 mm, than eyes with a longer axial length
(>28 mm).
Conclusions: Neglecting posterior corneal astigmatism yielded
significant estimation errors for total corneal astigmatism in patients
preparing for cataract surgery, especially in patients with larger
magnitude of KA, elder age, and relatively shorter axial length.
Error vectors between keratometric (KA) and total astigmatism (PA),
and the estimation errors categorized by the astigmatism type of KA.
Influence factors on estimation errors.
Commercial Relationships: Tianyu Zheng, None; Yi Lu, None
Support: Supported by the National Natural Science Foundation
of China (NSFC) No. 81270989 and No. 81300747, Specialized
Research Fund for the Doctoral Program of Higher Education
(SRFDP) No. 20130071120096, Trans-Century Training Program
for 100 excellent academic leaders by Shanghai health bureau No.
XBR2011056.
©2015, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
to reproduce any abstract, contact the ARVO Office at pubs@arvo.org.
ARVO 2015 Annual Meeting Abstracts
Program Number: 1905 Poster Board Number: C0213
Presentation Time: 11:00 AM–12:45 PM
Comparison of Postoperative Change in Corneal Astigmatism
after Small Biplanar Incision Cataract Surgery With and
Without Wound Suture as Performed by a Resident Surgeon
Michelle Overturf1, 2, Bethany Markowitz1, 2. 1Ophthalmology,
USC School of Medicine/Palmetto Health, Columbia, SC;
2
Ophthalmology, Dorn VA Hospital, Columbia, SC.
Purpose: Corneal incisions relax corneal steepening along the axis
of incision. Thus, the temporally placed self-sealing clear corneal
incision (CCI) used during cataract surgery is known to slightly
reduce against the rule (ATR) astigmatism. However, a surgeon
may choose to place a suture at the CCI site at the end of surgery,
to ensure the wound remains water tight. We hypothesized that the
reduction in ATR astigmatism seen from a temporal CCI wound
would be lessened when a suture was placed through the CCI as
compared to a sutureless CCI.
Methods: Twenty-two eyes with preoperative ATR astigmatism
(as determined by IOL Master K readings) had cataract surgery
performed via a biplanar CCI (made with a 2.4mm keratome) by the
same resident surgeon. A 10-0 nylon suture was placed through the
CCI wound at the end of surgery in 5 of the cases; the remaining had
no suture placed. There were no visible intraoperative wound changes
at the end of surgery, and all eyes were Seidel negative on postop day
1. All sutures were removed at postop week 3. Subjective manifest
refraction was measured at postop week 5. Eyes that had a CCI
wound suture placed were then compared to those without a suture.
Results: Of the 5 eyes that had a CCI wound suture placed, the mean
preop corneal astigmatism was 0.76 diopters; the mean change in prev.s. postop corneal astigmatism was -0.6 diopters. Of the 17 eyes that
did not have a suture placed, the the mean preop corneal astigmatism
was 0.762 diopters; the mean change in pre- v.s. postop corneal
astigmatism was -0.4 diopters.
Conclusions: A temporally placed self-sealing biplanar CCI is known
to decrease ATR astigmatism. A suture may be placed at the CCI
wound to ensure the eye remains water tight at the end of surgery. At
postop week 5 there was no difference in the change in ATR corneal
astigmatism in eyes that had a suture initially placed as compared
with those that had no suture placed. Due to inexperience, resident
surgeons are more likely to induce wound instability, and thus to use
a suture for securing the CCI wound. Resident surgeons should not
hesitate to use a suture to secure the CCI wound at the end of surgery;
the final change in postop corneal astigmatism, in eyes with preop
ATR astigmatism, will not be affected by placement of a suture at the
CCI wound.
Commercial Relationships: Michelle Overturf, None; Bethany
Markowitz, None
Program Number: 1906 Poster Board Number: C0214
Presentation Time: 11:00 AM–12:45 PM
The relationship between corneal astigmatism and refractive
astigmatic error in pseudophkic eyes
Phillip J. Buckhurst1, Catriona Hamer1, Hetal Buckhurst1, Christine
Purslow2, 1, Nabil Habib3, 1. 1School of Health Professions, Plymouth
University, Plymouth, United Kingdom; 2Cardiff University, Cardiff,
United Kingdom; 3Royal Eye Infirmary, Plymouth, United Kingdom.
Purpose: Following cataract surgery any uncorrected corneal
astigmatism translates into ocular refractive astigmatic error (RAE).
When implanting a toric intraocular lens (IOL) the power and
orientation of the IOL is determined after assessment of corneal
power via keratometry or topography. A limitation of both these
techniques is that they only evaluate the anterior corneal surface.
Schiempflug tomography assesses both the anterior and posterior
corneal surface allowing determination of the total corneal astigmatic
error. This study examines the relationship between corneal
astigmatism and RAE.
Methods: The study examined 80 subjects (74.8±9.6 years) who
had undergone small incision sutureless cataract surgery with
postoperative corneal astigmatism >0.75DC. All subjects were
implanted with a monofocal, non-toric, aspheric IOL. Scheimpflug
tomography was used to determine the postoperative anterior
corneal astigmatism (ACA) as well as the total corneal astigmatism
(TCA). An investigator masked to the tomography results conducted
subjective refraction to determine RAE. The astigmatic power of the
cornea and the overall manifest refraction were assessed following
conversion into vector format (J0/J45). The relationship between ACA,
TCA and RAE was assessed through repeated measures ANOVA and
a stepwise multiple linear regression.
Results: The mean RAE, ACA and TCA were 1.11D (J0: 0.73±1.05;
J45: -0.01±0.67), 1.07D (J0 0.12±1.02; J45: 0.01±0.67) and 1.30D (J0:
0.38±1.09; J45: 0.00±0.86), respectively. Along the horizontal power
meridian (J0), ACA was found to be significantly lower than RAE
(p<0.05). In contrast TCA was found to be similar to RAE along both
J0 and J45 (p>0.05). Corneal astigmatism was found to account for
only 18% of the variation in RAE; this stepwise regression model
found that only TCA and not ACA was a significant predictor of
RAE.
Conclusions: When compared to the anterior corneal astigmatism,
total corneal astigmatism showed a greater association with the
overall refractive corneal astigmatism. These results would suggest
that it is important to select the power and position of toric IOL in
accordance with total corneal astigmatic power rather than just the
anterior corneal astigmatism.
Commercial Relationships: Phillip J. Buckhurst, Bausch and
Lomb (F); Catriona Hamer, None; Hetal Buckhurst, None;
Christine Purslow, None; Nabil Habib, None
Program Number: 1907 Poster Board Number: C0215
Presentation Time: 11:00 AM–12:45 PM
Quantitative evaluation of predicted residual astigmatism
between manufacturers of toric intraocular lenses with differing
astigmatic corrections
Fatma Dihowm1, 3, Lauren Jabra2, Samir I. Sayegh1. 1The Eye Center,
Champaign, IL; 2University of Illinois, Chicago, IL; 3Prince George’s
Hospital Center, Cheverly, MD.
Purpose: To compare methodologies of major manufacturers of toric
intraocular lenses (tIOL) producing lenses with different amount of
astigmatism. Work by our group and others have established that a
number of companies use fixed ratio methods for prediction of tIOL
implants. As we anticipate an expansion in the range of correction
offered with the wide acceptance of tIOL, predictive comparisons are
warranted.
Methods: Based on the spectrum of FDA approved tIOL produced
by one company and their fixed toricity ratio as inferred from
their online calculator and recent literature and using our validated
Universal IOL calculator in constant toricity mode, we generated
120 cases for comparison to the range of astigmatism offered by
another company with FDA approved tIOLs in a different astigmatic
correction range. These cases covered a wide range of spherical
power, mean K and amount of astigmatism.
Results: Both companies tIOLs predicted a constant amount of
residual astigmatism independent of the spherical power of the
implant. That amount of astigmatism however differed between the
two companies.
Conclusions: Even among major companies using a fixed toricity
ratio method the residual astigmatism differs for the same eye with
©2015, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
to reproduce any abstract, contact the ARVO Office at pubs@arvo.org.
ARVO 2015 Annual Meeting Abstracts
the same amount of astigmatism and identical power of correction
tIOL.
Commercial Relationships: Fatma Dihowm, None; Lauren Jabra,
None; Samir I. Sayegh, None
Support: No support
Program Number: 1908 Poster Board Number: C0216
Presentation Time: 11:00 AM–12:45 PM
Correction of corneal astigmatism using femtosecond laser
intrastromal incisions during cataract surgery
Li Wang1, 2, Lai Jiang1, Zaina Al-Mohtaseb1, Douglas D. Koch1.
1
Cullen Eye Institute, Dept Ophthalmology, Baylor College of
Medicine, Houston, TX; 2Shanxi Eye Hospital, Taiyuan, China.
Purpose: To evaluate the effectiveness of femtosecond laser
intrastromal (IS) incisions made during cataract surgery to reduce or
prevent increase in corneal astigmatism.
Methods: Using the Catalys laser (Abbott Medical Optics), IS
incisions were created according to the nomogram proposed by
Julian Stevens, modified to take into account posterior corneal
astigmatism. The incisions were placed at diameter of 8 mm and
a depth of 20% from both anterior and posterior corneal surfaces.
Corneal astigmatism was measured before and 3 weeks or more
after the surgery with Lenstar, Cassini, and Atlas. Inclusion criteria
are consecutive cases with post-operative follow-up of 3 weeks or
longer and best-corrected visual acuity of 20/30 or better. OCT scans
(RTVue, Optovue) were also obtained postoperatively to assess the
location of the IS incisions.
Results: Forty-two eyes of 38 patients were included with paired
incisions (30° - 60°) in 35 eyes and a single incision (35° - 60°) in
7 eyes. Preoperatively, 4.8%, 19.0%, 47.6% and 61.9% of eyes had
corneal astigmatism (Lenstar) within 0.25 D, 0.50 D, 0.75 D, and
1.0 D, respectively; postoperatively, the percentages of eyes with
manifest cylinder in each bin significantly increased to 47.6%, 88.1%,
97.6%, and 100%, respectively (all P<0.01). With OCT, the IS
incision locations were 18.5% ± 5.9% (SD, range 8.4-31.7%) depth
anteriorly and 35.2% ± 8.3% (range 16.8-52.7%) depth posteriorly.
Conclusions: IS incisions with femtosecond laser significantly
decreased corneal astigmatism. However, some femtosecond laser
incisions were located more anteriorly than planned. More eyes
will be enrolled, a nomogram will be developed, and effects of new
software will be assessed.
Commercial Relationships: Li Wang, Ziemer (R); Lai Jiang,
None; Zaina Al-Mohtaseb, None; Douglas D. Koch, Abbott
Medical Optics (C), Alcon (C), Carl Zeiss Meditec (F), iOptics (F),
TrueVision (F), Ziemer (F)
Support: Research to prevent blindness
Program Number: 1909 Poster Board Number: C0217
Presentation Time: 11:00 AM–12:45 PM
Intra-lenticular femtosecond laser cavitation threshold variations
Georg Schuele, David Dewey, Phillip Gooding, Mike Simoneau,
Alexander Vankov. R&D, Abbott MEdical Optics / OptiMedica,
Sunnyvale, CA.
Purpose: Femtosecond laser-assisted laser cataract surgery has
gained a significant interest due to its ability to create perfectly
sized capsulotomies as well pre-fragment the lens to facilitate easy
removal of the lens during cataract surgery. In this paper we present
measurements of intra-lenticular variation of cavitation threshold
using fresh porcine lenses and compare it to optical modeling result.
Methods: A water-filled cuvette with embedded hydrophone was
connected and synchronized with a standard CATALYS ® System
to allow synchronized exposure and reading of cavitation events.
Specialized software was developed to probe full fields within the
cuvette volume for cavitation thresholds. Initially the cavitation
threshold variation of water was measured and acted as a system
specific baseline. Fresh porcine lenses were placed in the cuvette and
the same fields retested for cavitation thresholds.
An optical model of the CATALYS ® System in ZEMAX software
along with a standard lens model was used to calculate Strehl-ratios
of different field points within the porcine lens. These data are
compared to the variations seen in experiments.
Results: Even for very fresh and clear porcine lenses cavitation
thresholds varied greatly throughout the different locations of the
lens. Within the center 3 mm radius mean threshold was increased
2.5 fold while the three star suture areas of the lens increased the
threshold up to 4 fold. Beyond the 3mm radius thresholds increased
even further to 6-8 fold threshold relative to water.
Optical simulations showed only minor variation of strehl-ratio of
0.2 which did not correspond to the significant higher variations in
threshold using porcine lenses.
Conclusions: We could demonstrate that significant variation of
cavitation threshold using femtosecond lasers exist even in clear fresh
porcine lenses. Optical modeling of the strehl-ratio does not predict
the measured variations. This might indicate that other tissue related
effects like the grin-lens effect or other tissue specific refractive index
variations will lead to focus distortions and with that to increased
cavitation threshold
Commercial Relationships: Georg Schuele, Abbott Medical Optics
(E); David Dewey, Abbott Medical Optics (E); Phillip Gooding,
Abbott Medical Optics (E); Mike Simoneau, Abbott Medical Optics
(E); Alexander Vankov, Abbott Medical Optics (E)
Program Number: 1910 Poster Board Number: C0218
Presentation Time: 11:00 AM–12:45 PM
Resident Training in Femtosecond Cataract Surgery: A National
Survey
Ruchi Shah. Ophthalmology, Loyola University Medical Center,
Maywood, IL.
Purpose: One of the newest advancements in cataract surgery is the
use of femtosecond laser. The percentage of residency programs that
have access to the femtosecond laser is not reported, and there is
limited data about resident training in femtosecond cataract surgery.
The purpose of this cross-sectional study is to determine how
ophthalmology residents in the United States are being trained to
perform femtosecond laser cataract surgery and identify any barriers
to incorporating it in resident curriculum.
Methods: ACGME-accredited ophthalmology residency programs
were mailed a survey inquiring about their access to femtosecond
lasers and the role in resident education. Surveys were anonymous
and respondent results were tabulated in an excel spreadsheet.
Results: We had a response rate of 80%. 74% of academic
departments did not utilize a femtosecond laser for cataract surgery
©2015, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
to reproduce any abstract, contact the ARVO Office at pubs@arvo.org.
ARVO 2015 Annual Meeting Abstracts
but 50% planned on obtaining a laser within 5 years. Of those that do
utilize a femtosecond laser, 38% had a laser located at the ASC, 33%
at a private hospital and 33% at a VA Hospital. The most common
type of laser used was the Alcon LenSx followed by the AMO
Catalys. 79% residency programs do not train residents to undergo
femtolaser cataract surgery, but 55% plan to develop training within
5 years. The most perceived barrier to resident access was cost,
followed by laser location and inexperienced attendings. Among
the 21% of residency programs that train their residents to perform
femtosecond cataract surgery, most of the residents begin preclinical
training (55%), observing (43%), and performing (90%) cases
during PGY4 level. Of the programs that perform laser cases, 55%
of residents perform 1 to 9, 15% perform 10 to 24, and 25% perform
between 25-100.
Conclusions: The majority of academic department do not use
femtosecond lasers for cataract surgery and the majority of residency
program do not train their residents to use this technology. The
largest barrier to resident access is cost. However among academic
departments that do not yet have a femtosecond laser, about half of
the programs plan on developing hands-on laser access for residents
within the next five years. In residencies that do currently teach
residents to perform femtosecond cases, most training occurs during
their PGY4 year and the majority of residents graduate each with a
small total of 1 to 9 cases.
Commercial Relationships: Ruchi Shah, None
Support: Dr. Brian Sullivan
(766mm vs. 1035mm, p<0.001) and demonstrated a significantly
higher rate of complications at a fixed laser energy setting including
an increase in tags (2/6), one demonstrable capsule rip and significant
decrease in circularity (0.9, p<0.05). No problems were encountered
during fragmentation.
Conclusions: The Ziemer LDV Z8 utilises a precision optical laser
through a liquid interface, delivering reduced energy with each
pulse. We found that the platform created a reliable and circular
capsulotomy but with increased resistance to tension with larger
capsule sizes. Extreme corneal oedema induced by excessive storage
showed a predictable and commensurate reduction in quality of
capsulotomy, albeit at fixed energy. Further investigation to determine
the effect of capsulotomy size on resistance to tension and the limits
of corneal opacification for safe procedure are warranted in human
eyes.
Commercial Relationships: Geraint P. Williams, Ziemer (F);
Benjamin L. George, None; Yoke R. Wong, None; Heng Pei Ang,
None; Xin Yi Seah, None; Suzana B. Ita, None; Yu-Chi Liu, None;
Shian C. Tay, None; Donald Tan, Ziemer (C); Jodhbir S. Mehta,
Ziemer (C)
Support: TCR Eyesite Supported by National Research Foundation
of Singapore-Funded Translational and Clinical Research Programme
Grant NMRC/TCR/ 01020-SERI/2013. Geraint P Williams’ SERI/
SNEC fellowship is supported by a Dowager Eleanor Peel Trust
Travelling Grant and a Royal College of Ophthalmology/Pfizer
Ophthalmic Fellowship.
Program Number: 1911 Poster Board Number: C0219
Presentation Time: 11:00 AM–12:45 PM
The effects of the Ziemer LDV Z8 low-energy, high-frequency
liquid optic interface system during femtosecond laser lens
capsulotomy and fragmentation
Geraint P. Williams1, 2, Benjamin L. George1, Yoke R. Wong3, Heng
Pei Ang1, Xin Yi Seah1, Suzana B. Ita3, Yu-Chi Liu1, 2, Shian C. Tay4,
Donald Tan1, 2, Jodhbir S. Mehta1, 2. 1Tissue Engineering and Stem
Cell Group, Singapore Eye Research Institute, Singapore, Singapore;
2
Corneal and External Eye Disease Service, Singapore National Eye
Centre, Singapore, Singapore; 3Biomechanics Laboratory, Singapore
General Hospital, Singapore, Singapore; 4Department of Hand
Surgery, Singapore General Hospital, Singapore, Singapore.
Purpose: To determine the effects of the low-energy, high-frequency
Ziemer LDV Z8 liquid interface femtosecond laser platform during
capsulotomy and lens fragmentation.
Methods: Ex vivo cadaveric porcine eyes harvested at <6 post hours
enucleation were evaluated with the Ziemer LDV Z8 femtosecond
laser during fragmentation (8 segment, 5.3mm diameter, 0.8mm
height, cut speed 50mm/s, energy 90%) for different capsulotomy
sizes (4, 5 or 6mm diameter, 2.8mm height, cut speed 10mm/s,
energy 100%). Lens capsules were removed for evaluation of edge
by circularity (Image J) and scanning electron microscopy (SEM).
Lens capsule strength was determined by the single column universal
testing system (Instron).
Results: All procedures were completed successfully without
complication. Of 18 eyes undergoing Femto-cataract with the Z8
laser, the total time to completion was 216 seconds (SD 43s). There
was a significant difference in the time taken to complete surgery
with increased capsulotomy sizes (p=0.01). The lens capsule
circularity achieved was high at 0.98 with no demonstrable influence
of size with larger capsulotomy (p=NS). Small removable tags
were evident on SEM in 2/18 cases but otherwise smooth edges
were observed. The capsule tension was measured at 79mN at 4mm
and 139mN at 6mm (p<0.01)). When inducing corneal oedema by
prolonged storage (>24 hours), the mean corneal thickness increased
Program Number: 1912 Poster Board Number: C0220
Presentation Time: 11:00 AM–12:45 PM
Biometric System Repeatability in Femtosecond Laser-Assisted
Cataract Surgery
Dustin Morley, Gary Gray. R&D, Lensar, Orlando, FL.
Purpose: This study defines a FLACS biometric system repeatability
measure based on the probability of image processing errors having
an influence on the construction of a 3D lens model and subsequent
laser treatment, and uses statistical analysis to evaluate repeatability
as a function of the number of biometric images acquired and the
automatic image processing performance.
Methods: Using MATLAB, a model was constructed to assess the
impact of image processing errors on laser treatment. The model
consisted of a biometric scan yielding N images, which were
automatically processed by algorithms that either successfully
processed, erroneously processed, or left unprocessed each image.
The probability of each outcome is specified as an input parameter
to the model, along with N. If N > 2, the model includes the use of
outlier removal techniques when combining the images into the 3D
lens model. With outlier removal, if there are fewer erroneously
processed images than correctly processed images, the 3D lens model
will be constructed as though the erroneously processed images had
been left unprocessed, thus removing their influence on the treatment.
The model uses established probability laws to compute the biometric
system error rate (the probability of image processing errors
influencing treatment) for the given input parameters. Biometric
system repeatability is defined as the inverse of the error rate. Thus,
an error rate of 1% yields a repeatability of 100, meaning one would
expect to observe an error about once every 100 treatments.
Results: The MATLAB program was run on several different
parameter sets. For all parameter sets tested, an exponential
relationship was observed between the repeatability and the number
of images acquired in the biometric scan (R squared values greater
than 0.99). The parameter sets included per-image error rates (PIER)
ranging from 25% to 0.1% with per-image no-result rates of 0%
and 20%. For a PIER of 1%, the repeatability is 3 to 6 orders of
©2015, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
to reproduce any abstract, contact the ARVO Office at pubs@arvo.org.
ARVO 2015 Annual Meeting Abstracts
magnitude higher for a 10-image FLACS system than a 2-image
FLACS system.
Conclusions: FLACS biometric system repeatability can be
improved by orders of magnitude by acquiring a larger number
of images and applying outlier removal algorithms. Currently,
commercial FLACS lasers are configured to use either 10 images or
2 images in the biometric scan. Higher biometric system repeatability
may help in minimizing the risk of intra-operative complications.
Commercial Relationships: Dustin Morley, Lensar (E); Gary
Gray, Lensar (E)
Program Number: 1913 Poster Board Number: C0221
Presentation Time: 11:00 AM–12:45 PM
Accuracy of toric intraocular lens alignment and predicted
residual astigmatism using a 3D computer-guided visualization
system in femtosecond laser-assisted cataract surgery
Ildamaris Montes de Oca, Eric J. Kim, Li Wang, Sumitra
Khandelwal, Mitchell Weikert, Zaina Al-Mohtaseb, Douglas D. Koch.
Ophthalmology, Cullen Eye Institute, Baylor College of Medicine,
Houston, TX.
Purpose: To evaluate the accuracy of toric intraocular lens alignment
and predicted residual astigmatism in femtosecond laser-assisted
cataract surgery using a 3D computer-guided visualization system
Methods: In this prospective cohort study, one eye of each patient
receiving a toric intraocular lens (IOL) and femtosecond laser
cataract surgery was enrolled. Four anterior segment surgeons at a
single academic center performed all surgeries. Preoperatively, all
patients received corneal topography measurements by the Lenstar,
Galilei, and Cassini devices. The 3D computer-guided visualization
system used keratometry values measured by the Cassini to create an
optimized plan for the main incision location, toric IOL alignment,
and predicted residual astigmatism. The IOL model was chosen
by the surgeon based on the Baylor toric nomogram. The Catalys
(AMO) femtosecond laser was used for capsulectomy and nuclear
fragmentation. Additionally, two intrastromal marks were created by
the femtosecond laser at the intended toric meridian using manual
ink marks as a guide. Intraoperatively, the 3D system was used to
guide placement of the main incision and align the toric IOL. The
position of the femtosecond marks relative to the IOL axis was noted
intraoperatively. At three weeks postoperatively, patients received
corneal topography scans with the same devices. The position of
the toric IOL and the femtosecond marks were noted at slit lamp
examination. The manifest refraction and corrected distance visual
acuity were also measured.
Results: The study will enroll 50 patients. Preoperatively and
intraoperatively (n=13), our preliminary results found that the mean
predicted residual astigmatism was -0.29 ± 0.24 D [-0.61 to 0.20],
and the mean difference between the femtosecond mark and the
toric IOL meridians was 1.30 ± 1.84 degrees [0 to 5]. Postoperative
results (n=4) showed that the mean residual astigmatism was 0.44 ±
0.31 D [0 to 0.75]. The mean error in the 3D computer-guidedance
system was 3.50 ± 1.91 degrees [1 to 5]. The mean IOL rotation
postoperatively was 0.75 ± 0.96 degrees [0 to 2]. In all patients (n=4),
the CDVA was 20/25 or better.
Conclusions: Additional patients are currently being enrolled and
final results and conclusions will be presented. The performance of
the 3D computer-guided visualization system will be discussed.
Commercial Relationships: Ildamaris Montes de Oca, None; Eric
J. Kim, None; Li Wang, Ziemer (R); Sumitra Khandelwal, None;
Mitchell Weikert, Ziemer (C); Zaina Al-Mohtaseb, None; Douglas
D. Koch, Abbott Medical Optics (AMO) (C), Alcon Laboratories, Inc
(C), I-Optics (C), Ziemer (C)
Program Number: 1914 Poster Board Number: C0222
Presentation Time: 11:00 AM–12:45 PM
Do toric IOL calculators accurately predict the shift in
orientation of the steepest corneal meridian following cataract
surgery?
Catriona Hamer1, 2, Nabil Habib2, 1, Hetal Buckhurst1, Christine
Purslow1, 3, Phillip J Buckhurst1. 1Optometry, Plymouth University,
Plymouth, United Kingdom; 2Royal Eye Infirmary, Derriford
Hospital, Plymouth, United Kingdom; 3School of Optometry &
Vision Sciences, Cardiff University, Cardiff, United Kingdom.
Purpose: To provide accurate astigmatic visual correction after
cataract surgery, a toric intraocular lens (IOL) needs to be accurately
aligned with the steepest post-operative corneal meridian. Toric IOL
calculators, based on the oblique cross cylinder formulae, are used
to predict the orientation of the post-operative steepest meridian.
These calculators assume that both corneal astigmatism and surgical
incisions’ astigmatic effect act like two thin toric lenses in contact.
The study aims to verify the accuracy of pre-surgical toric IOL
calculator algorithms designed to predict the change in the corneal
meridian orientations following cataract surgery.
Methods: Prospective interventional study where 145 subjects
(74.8±9.6 years) had small incision sutureless cataract surgery with
a clear corneal incision placed obliquely to the steepest corneal
meridian. Scheimpflug tomography was conducted pre-operatively
and at 3-6 weeks post-operatively. The true location of the corneal
incision was assessed postoperatively through slit lamp examination.
Measurements were used to determine the predicted postoperative
steepest meridian shift and the actual axis change that occurred
following the surgery.
Results: The median pre-operative corneal astigmatism was 0.74D
(IQR 0.45, 1.10D). The mean location of the superior-temporal
corneal incision was 7.6±56.9° from the steepest corneal meridian.
The predicted median shift in steepest axis was 11.75° (IQR 6.1,
24.8°) towards the incision according to the toric calculators, but
the median actual change was only 4.8° (IQR -5.0, 20.2°). The toric
calculators significantly overestimated the overall change in axis for
this cohort (p<0.001), and a poor correlation was found between the
predicted and actual corneal axis change (=0.12, p= 0.28).
Conclusions: The oblique cross cylinder formulae used in toric IOL
calculators overestimate the shift in orientation of the steepest corneal
meridian following cataract surgery. These findings would suggest
that positioning a toric IOL according to the predictions of the
calculator can result in greater misalignment than simply positioning
the lens according to the original corneal steepest meridian.
Commercial Relationships: Catriona Hamer, None; Nabil Habib,
None; Hetal Buckhurst, College of Optometrists (F); Christine
©2015, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
to reproduce any abstract, contact the ARVO Office at pubs@arvo.org.
ARVO 2015 Annual Meeting Abstracts
Purslow, Spectrun Thea (E); Phillip J Buckhurst, Bausch and Lomb
(C), The College of Optometrists (F)
Support: Plymouth University Unrestricted PhD funding
Program Number: 1915 Poster Board Number: C0223
Presentation Time: 11:00 AM–12:45 PM
Integrating toric and spherical evaluation in Universal
Intraocular Lens Calculator
Samir I. Sayegh. EYE Ctr Anterior- Vitreoretinal Surg, Eye Center/
The Retina Center, Champaign, IL.
Purpose: To demonstrate the need for integration of the spherical
power calculation and the recommended toric correction in IOL
calculation and to offer a practical implementation.
Methods: A review of the methods offered by a majority of
manufacturers of toric IOLs and followed almost universally by
surgeons was performed.
Calculations of IOL power and toricity based on these methods
was analyzed and executed alongside a theoretical analysis of the
underlying methods and algorithms.
Results: A number of cases were identified where the standard
sequential methods resulted in suboptimal choice of lenses. These
were then calculated with our Universal Calculator in simultaneous
mode and resulted in selections demonstrably preferable to those of
the standard methods. The dominant methodologies were identified
as a form of “greedy algorithms” which are known to have the
possibility of being suboptimal.
Conclusions: The usual sequential method of toric IOL is
suboptimal. A method and an implementation providing better
choices is demonstrated.
Commercial Relationships: Samir I. Sayegh, None
Program Number: 1916 Poster Board Number: C0224
Presentation Time: 11:00 AM–12:45 PM
Comparing toricity ratios across leading toric IOL manufacturers
Lauren Gabra2, 1, Samir I. Sayegh2. 1University of Illinois at Urbana
Chamapaign, Urbana, IL; 2The Eye Center, Champaign, IL.
Purpose: To determine the toricity ratio for toric intraocular lenses
for leading toric IOL manufacturers
Methods: High, average and low axial length values were crossed
with high, average and low averages of mean corneal power values
to generate a 3x3 matrix of paired values. These values were used
to generate a selection of a toric intraocular lens for manufacturers
approved in USA or/and Europe. Using values of residual
astigmatism computed by each toric calculator, a toricity ratio was
generated for each pair of axial length and mean corneal power
corresponding to each manufacturer. These values were compared
to values published by the manufacturers and those predicted in the
literature.
Results: Our algorithm helped distinguish the manufacturers using
a constant toricity ratio from those using a variable one. Those using
a constant ratio were using around 1.45; while those using a variable
ratio ranged from 1.3 to 2.3. These variable ratio results are consistent
with the calculation published in the literature and our theoretical
framework and confirm in particular that as axial length and mean K
increase so does the toricity ratio.
Conclusions: Our algorithms contribute to identifying manufacturers
using a constant toricity, and the precise variation of toricity ratio
used by other manufacturers. This technique will further improve
our ability to select appropriate toric IOLs for our patients. The
relevant methodologies have been integrated into our Universal IOL
calculator.
Commercial Relationships: Lauren Gabra, Eye Center (F); Samir
I. Sayegh, None
Program Number: 1917 Poster Board Number: C0225
Presentation Time: 11:00 AM–12:45 PM
Association of limbal incision distance from the axis of
astigmatism for Acrysof Toric intraocular lens implantation
Adnan Mallick, Carolyn Shih, Tehilla S. Steiner, Rachel Chu, Jules
Winokur. Department of Ophthalmology, North Shore-Long Island
Jewish Health System, Manhasset, NY.
Purpose: This study aimed to determine the independent association
of distance of limbal cataract incision from pre-operative axis of
astigmatism to post-operative degree of manifest astigmatism in
patients with Toric intraocular lens (IOL) implantation.
Methods: In this retrospective study, 81 eyes with cataract and
mild to high corneal astigmatism (range 0.75 to 4.25 diopters) were
analyzed. 59 patients were implanted with a SN6AT3 lens to correct
astigmatism <1.50 diopters (D). 11 patients were implanted with a
SN6AT4, 6 patients with a SN6AT5, 4 with a SN6AT7, and 1 with
a SN6AT9. Mean age of patients was 72, with 38 male subjects. All
of these patients underwent phacoemulsification with Acrysof Toric
IOL implantation (2.75 mm incision). Main outcome measurement
was degree of postoperative astigmatism in relationship to the limbal
incision distance from the axis of astigmatism.
Results: Pre-operatively, mean astigmatism was 1.59 D (range 0.75
to 4.25 D). Post-operatively, mean astigmatism decreased to 0.75 D
(range 0 to 2.75 D). No significant difference was found in the mean
postoperative astigmatism for patients in which limbal incision was
made ≤25 degrees from the axis of astigmatism (n=34), and patients
in which limbal incision was made >25 degrees from the axis of
astigmatism (n=47); [0.80 D vs. 0.71 D, p=0.26]. Patients implanted
with SN6AT3 lenses (n=59) showed less post-operative astigmatism
than patients implanted with other toric lenses (n=22); [0.66D vs.
1.00D, p<0.05].
Conclusions: Toric IOLs are effective in reducing manifest
astigmatism. The distance of limbal cataract incision from the preoperative axis of astigmatism does not appear to influence the degree
of post-operative manifest astigmatism. There may be no benefit to
moving the site of incision to coincide with an axis of astigmatism.
Commercial Relationships: Adnan Mallick, None; Carolyn Shih,
None; Tehilla S. Steiner, None; Rachel Chu, None; Jules Winokur,
None
Program Number: 1918 Poster Board Number: C0226
Presentation Time: 11:00 AM–12:45 PM
One-week Telephone Interview After Cataract Surgery
David DeMill1, Roni M. Shtein1, David C. Musch1, Leslie M. Niziol1,
Stefanie Sherman2, Bamidele Otemuyiwa2, Muazzum Shah2, Shahzad
Mian1. 1Ophthalmology and Visual Sciences, University of Michigan,
Ann Arbor, MI; 2Medical School, University of Michigan, Ann Arbor,
MI.
Purpose: To determine if a one-week post-cataract surgery telephone
call may replace an office visit and to report on characteristics
associated with unplanned patient visits within the first month after
surgery.
Methods: Retrospective study of 826 consecutive patients who
had phacoemulsification and intraocular lens implantation between
January 1, 2014 and September 31, 2014 at a single surgery center.
All patients were scheduled for a one-week post-cataract surgery
structured telephone interview with a certified ophthalmic technician.
Patients were categorized into 3 groups: those that did not require an
office visit between postoperative (PO) day 1 and PO month 1 (Group
1), and those that had a planned (Group 2) or unplanned (Group 3)
office visit. Groups were compared with Chi-square or Fisher exact
tests for categorical variables and ANOVA for continuous variables;
©2015, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
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ARVO 2015 Annual Meeting Abstracts
post-hoc pairwise comparisons with Bonferroni adjustments were
used as needed.
Results: 637 patients (77%) had a telephone interview attempted,
with completion in 565 (68%) patients and no answer with 72
(9%). 154 patients (19%) had the call cancelled due to either an
unplanned or planned office visit prior to the call. 35 patients (4%)
had missing telephone call data. 11 patients (1%) were asked to come
in for an office visit after the phone call; none of them had a serious
complication. Overall, 605 patients (73%) did not require an office
visit, 166 (20%) had a planned visit, and 55 (7%) had an unplanned
visit.
Significant differences were noted between the 3 groups with respect
to gender (54.8% female in Group 1, 62.7% in Group 2, and 74.6%
in Group 3; p = .0063), first or second cataract surgery (51.4% first
cataract surgery in Group 1, compared to 63.3% in Group 2 and
69.1% in Group 3; p = .0023), preoperative intraocular pressure
(IOP) (15.0 mmHg in Group 1, 16.2 in Group 2, and 14.8 in Group 3;
p = .0001), one-day PO IOP (17.8 mmHg in Group 1, 21.5 in Group
2, and 17.5 in Group 3; p = <.0001), and one-month PO IOP (14.1
mmHg in Group 1, 14.8 in Group 2, and 14.1 in Group 3; p = .0306).
Conclusions: Replacing a one-week post-cataract surgery office
visit with a one-week telephone call was not associated with any
adverse events in the first month after cataract surgery. Improved
preoperative education for those having their first cataract surgery
could potentially decrease unintended visits after surgery.
Commercial Relationships: David DeMill, None; Roni M. Shtein,
None; David C. Musch, None; Leslie M. Niziol, None; Stefanie
Sherman, None; Bamidele Otemuyiwa, None; Muazzum Shah,
None; Shahzad Mian, None
Program Number: 1919 Poster Board Number: C0227
Presentation Time: 11:00 AM–12:45 PM
A Novel Eye Drop Application Monitor to Assess Patient
Compliance Relative to the Shape of Eye Drop Bottles Following
Cataract Surgery
Mia Allen1, Ariana Allen1, Alexandra konowal1, Gabriel M. Gordon2,
Alexander M. Eaton2. 1Konowal Vision Center, Estero, FL; 2Retina
Health Center, Fort Myers, FL.
Purpose: The purpose of the study was to evaluate patient
compliance with prescribed eye drop in relation to bottle shape using
a novel eye drop application monitor (EDAM). We hypothesize that
subjects will dispense the correct amount of medication more often
when using rounded bottles compared to flat bottles.
Methods: Thirty eight subjects were instructed on use of the EDAM.
The EDAM device was used for one week with post-operative eye
drop applications following cataract surgery using two round bottles
and one flat bottle. Patients recorded a compliance log of how many
drops were dispensed, how many landed in the eye, outside the eye,
or half in and half out. The EDAM was returned for video analysis
to objectively determine the patient’s eye drop use and delivery.
Variation between subjects’ perceived and actual drops dispensed and
perceived and actual drops in was assessed for each bottle type, and
the two bottle shapes to each other.
Results: The subject’s perceived drops dispensed were significantly
different than the actual drops dispensed for both bottle shapes,
varying from the prescribed regimen on average by 39% (p<0.001)
with a range of 0%-286% for the round bottle and 32% (P<0.001)
with a range of 0-129% for the flat bottle. There was a 41%
difference between the actual number of drops the patients dispensed
and the prescribed regimen (P<0.001) with a range of 0-282% for
the round bottle and 38% with a range of 0-100% for the flat bottle.
The subject’s perceived drops in were significantly different than the
actual drops in for both bottle shapes, varying from the prescribed
regimen by 23% (0%-129%, p<0.001) for the round bottle and
27% (o%-129%, p<0.001) for the flat bottles. The subjects drops in
varied from the prescribed regimen by 37% (0%-96% and 0%-100%,
p<0.001 for both) of their drops in for both bottle shapes. Neither
the perceived nor the actual difference in drops dispensed (p=0.56
and 0.79, respectively) and drops in (p=0.6 and 0.96, respectively)
between the round and flat bottle types was significantly different.
Conclusions: While we found no significant difference between
the two bottle shapes with respect to drops dispensed or drops
in, subjects using the round bottle tended to vary more from the
prescribed regimen, contrary to our hypothesis.
Commercial Relationships: Mia Allen, None; Ariana Allen, None;
Alexandra konowal, None; Gabriel M. Gordon, None; Alexander
M. Eaton, Retina Health Center (I), Retina Health Center (P)
Program Number: 1920 Poster Board Number: C0228
Presentation Time: 11:00 AM–12:45 PM
Perioperative Antibiotic Use among San Antonio Cataract
Surgeons
Mason A. Schmutz, Kundandeep Nagi. Ophthalmology, University
of Texas Health Science Center at San Antonio (UTHSCSA), San
Antonio, TX.
Purpose: To study and establish a community standard for the
use of antibiotics in cataract surgery. To identify the practices and
preferences of San Antonio ophthalmologists as they relate to cataract
surgery.
Methods: A 20 question survey was administered to San Antonio
ophthalmologists. It was distributed to all University of Texas Health
Science Center at San Antonio(UTHSCSA) ophthalmologists as well
as to members of the San Antonio Society of Ophthalmology(SASO).
Surveys were administered by email and in person. The email version
was administered through a link to an online survey at surveymonkey.
com. IRB approval was obtained through UTHSCSA.
Results: Anesthesia was reportedly given by a retro or peribulbar
technique 47.7% of time, compared with 43.5% for topical/
intracameral. General anesthesia was only used 4.5% of the time.
Clear cornea incision was identified as the preferred method of
primary wound formation 86.6% of the time, followed by scleral
tunnel at 11.7%. These wounds were closed with wound hydration
82.2% of the time and with suture 17.8%.
Preoperatively 79.2% of physicians report using antibiotic drops for
a time period ranging from one drop on the day of surgery to several
days of drops. The other 20.8% of surgeons did not give antibiotics
in the preoperative setting. Intraoperatively 50% of surgeons gave
topical antibiotics, 29.2% intracameral, 25% subconjunctival, 8.3%
subtenons and 29.2% did not use antibiotics at this stage. No one
reported giving IV antibiotics at any point and no one used antibiotics
in their irrigating solution. Postoperatively 100% of surgeons
prescribed topical antibiotics.
All of the physicians surveyed routinely prepped with povidoneiodine prior to surgery, 20.8% reported employing 2 or more
applications. In cases of iodine allergy 37.5% of surgeons said they
still use povidone-iodine, and another 8% perform a skin test.
Conclusions: Through this research we have identified the general
styles and preferences of local San Antonio ophthalmologists. Our
results demonstrate the community standard for antibiotic and
anesthetic use in cataract surgery. We also believe that this research
helps provide a picture of the national landscape and highlights
current trends in cataract surgery. It will be useful for physicians in
training as they enter the work force.
Commercial Relationships: Mason A. Schmutz, None;
Kundandeep Nagi, None
©2015, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
to reproduce any abstract, contact the ARVO Office at pubs@arvo.org.
ARVO 2015 Annual Meeting Abstracts
Program Number: 1921 Poster Board Number: C0229
Presentation Time: 11:00 AM–12:45 PM
Objective outcomes of AT LISA Tri IOL in Conde de Valenciana
Ivo Ferreira-Rios. Segmento Anterior, Institucion Conde de
Valenciana, Mexico City, Mexico.
Purpose: To evaluate refractive and visual outcomes and contrast
sensitivity after cataract surgery with the implantation of AT LISA
trifocal intraocular lens (IOL)
Methods: Patients had bilateral cataract surgery and multifocal
diffractive IOL (AT Lisa tri 839 MP) implantation. A complete
ophthalmology examination was performed preoperatively and
postoperatively. The follow-up was 2 months. The main outcome
measures were uncorrected distance (UDVA), intermediate, and near
visual acuities, distance between visual axis and the center of the IOL
and aberrations (total, corneal, internal).
Results: The study comprised 16 eyes of 8 patients (mean age
59 years ± 5.2 [SD]; range 49 to 80 years). There was significant
improvement in uncorrected intermediate visual acuity, uncorrected
near, intermediate and near visual acuity. The postoperative refractive
status was within the range of +1.50 to -1.25 diopter. Total internal
aberrations decreased significantly (P<.001). FACT™ Contrast
Sensitivity Chart showed that contrast Sensitivity was below the
normal distribution.
Conclusions: The trifocal IOL improved near, intermediate, and
distance vision in presbyopic patients. The use of 3 foci provided
significant intermediate visual results without sacrificing near or
distance vision, however Contrast Sensitivity was below the normal
distribution.
Commercial Relationships: Ivo Ferreira-Rios, None
Program Number: 1922 Poster Board Number: C0230
Presentation Time: 11:00 AM–12:45 PM
Comparison of unilateral versus bilateral cataract surgery rates
Brandon J. Baartman, Yuan Cao, Alex Yuan, Richard Gans.
Ophthalmology, Cole Eye Institute - Cleveland Clinic, Cleveland,
OH.
Purpose: To determine what percentage of patients at the Cleveland
Clinic underwent cataract surgery on only one eye during a two-anda-half year follow-up period.
Methods: A retrospective chart review was performed in accordance
with Cleveland Clinic IRB policy. Electronic medical records of
patients treated at the Cleveland Clinic from January 1, 2012 to
August 1, 2014 were searched using CPT codes for cataract surgery
(66984 and 66982). Those surgeries associated with duplicate
Medical Record Numbers (MRNs) were considered bilateral cases,
whereas surgeries with unique MRNs were counted as single-eye
cases.
Results: From January 1, 2012 to August 1, 2014, there were 26,363
cataract surgeries performed at the Cleveland Clinic. Of these
cases, 20666 had duplicate MRNs, representing 10333 patients with
bilateral surgery. The remaining 5,697 cases were unilateral (36%).
Conclusions: Cataract surgery, often thought of as a bilateral
procedure, is most often performed as a “delayed sequential cataract
surgery”. This standard of care in the United States involves
performing the second cataract surgery days to months following
completion of the first1. Some surgeons have advocated performing
bilateral, same-day cataract surgery, or “immediate sequential cataract
surgery”1,2. We wanted to know the rate of unilateral cataract surgery
at our institution. Our study demonstrates that cataract surgery was
performed on one eye in 36% of cases at the Cleveland Clinic over
a two and a half year timeframe. Although we cannot exclude the
possibility that some of these patients had second-eye surgery outside
this time frame, this finding is surprising given the trends in practice
for most ophthalmologists, and warrants further analysis into the
possible reasons resulting in a decision to perform unilateral surgery.
1. Neel ST. A cost and policy analysis comparing immediate
sequential cataract surgery and delayed sequential cataract surgery
from the physician perspective in the United States. JAMA
Ophthalmol. 2014; 132(11):1359-1362.
2. Lundstrom M, Albrecht S, Roos P. Immediate versus delayed
sequential bilateral cataract surgery: an analysis of costs and patient
value. Acta Ophthalmol. 2009; 87(1):33-8.
Commercial Relationships: Brandon J. Baartman, None; Yuan
Cao, None; Alex Yuan, None; Richard Gans, None
Program Number: 1923 Poster Board Number: C0231
Presentation Time: 11:00 AM–12:45 PM
Survey of Current Cataract Surgery Practices in Ethiopia
Jordan J. Lee2, Lisa Park1. 1Ophthalmology, NYU School of
Medicine, Leonia, NJ; 2Bergen County Academies, Hoboken, NJ.
Purpose: Cataract is the leading cause of blindness and low vision in
Ethiopia. Greater than 0.5 million people are blind and approximately
1.2 million are severely visually impaired by this reversible
condition.1 It is estimated that in East Africa there are between 3,000
and 10,000 new cases per million population each year.2 Current
resources are insufficient to meet the surgical need, and the most
commonly performed procedure is extracapsular cataract extraction.
There are approximately 108 ophthalmologists in Ethiopia. 3 most
of whom are not trained in phacoemulsification. The purpose of this
study is to determine current practices in Ethiopian cataract surgery
and the adoption of modern phacoemulsification techniques.
Methods: An online questionnaire was administered during the
Annual Meeting of the Ophthalmologic Society of Ethiopia held in
Addis Ababa on October 3 & 4, 2014. All ophthalmologists present
at this meeting were invited to participate. Information on current
practices were collected and collated.
Results: 30 surveys were completed. Average number of years in
practice was 10 years (std dev = 6, range =2 to 23 years). 100% of
respondents reported currently performing extracapsular cataract
extraction. Numbers of ECCE performed per year ranged <300
n=9, 300-500 n=10, 500-1000, n=9, >500 n=2. 9 ophthalmologists
reported that they have performed phacoemulsification. Total number
of phaco cases per surgeon ranged from 10-2000. Teaching programs
where surgeons learned phaco included the following: Aravind n=3,
Vision Care Seoul n=2, Nepal n=2, Orbis n=2, HCP n=1, Caribbean
n=1. 82% of surgeons reported watching cataract surgery on the
internet. 52% of them were on Youtube. 18% of them were on the
ASCRS website and 12% from the AAO website.
Conclusions: The current level of cataract surgery in Ethiopia is
insufficient to meet the current clinical needs. Implementing more
teaching programs for phacoemulsification may help increase
availability of cataract surgery and achieve the “Vision 2020: The
Right to Sight” targets for treating avoidable blindness.
Commercial Relationships: Jordan J. Lee, None; Lisa Park, None
Program Number: 1924 Poster Board Number: C0232
Presentation Time: 11:00 AM–12:45 PM
A 10 year prospective study of cataract surgery in an ethnically
diverse population: Is the language barrier a risk factor for
posterior capsule rupture?
Jonathan Hyer1, Andrew Coombes1, Mark C. Westcott1, 2.
1
Ophthalmology, Royal London Hospital, London, United Kingdom;
2
Moorfields Eye Hospital, London, United Kingdom.
Purpose: The UK Cataract National Dataset has allowed the
identification and quantification of risks for posterior capsule
rupture (PCR) but data were not collected on patients’ proficiency
©2015, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
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ARVO 2015 Annual Meeting Abstracts
in English language or whether patients moved whilst operating.
A large proportion of our patients are Bangladeshi with multiple
co-morbidities for whom English is not their first language. We
performed a prospective perioperative survey to identify risk factors
for PCR, with particular attention to this subgroup.
Methods: Data were collected prospectively at a single NHS site
from January 2005. Operations were performed by surgeons of
all grades. Risk indicators for variations in the rate of PCR were
identified by univariate analyses using SPSSv22.
Results: Overall PCR rate was 3.7% from a total of 2912 operations
analysed. The majority were performed under local anaesthetic
(96.3%). Statistically significant risk indicators for PCR were small
pupil (p=0.003), dense nuclear sclerosis (p=0.003), patient movement
(p=0.003) and the use of vision blue (p=0.001). Mean pre-operative
best corrected LogMAR visual acuity was significantly worse in the
PCR group (p=0.01). Patient movement correlated significantly with
inability to speak English (p < 0.001) and could represent a surrogate
risk factor. 23% of subjects were non-English speaking, and these
eyes had statistically worse pre-operative vision, higher prevalence
of diabetes and retinopathy, dense cataracts, and intraoperative use of
vision blue (p= 0.001).
Conclusions: Our data confirm previously established risk factors
for PCR, and rates of these are higher in the non-English speaking
subgroup. Unsurprisingly, but previously unreported, is the
correlation of patient movement with PCR. Whilst this is difficult
to assess pre-operatively, it appears to be strongly associated
with patients who don’t speak English. This has implications for
operations performed under local anaesthetic and may suggest the
need for intraoperative interpreters in these eyes already at higher risk
of PCR.
Commercial Relationships: Jonathan Hyer, None; Andrew
Coombes, None; Mark C. Westcott, None
Program Number: 1925 Poster Board Number: C0233
Presentation Time: 11:00 AM–12:45 PM
Depth of Focus Measurement of an Ophthalmic Surgical
Microscope
Jim Schwiegerling1, Carl Chancy1, Ramon C. Dimalanta2. 1Optical
Sciences, University of Arizona, Tucson, AZ; 2Alcon Research,
Irvine, CA.
Purpose: The purpose of this study is to develop an objective and
reliable means for measuring the perceived depth of focus for surgical
microscopes.
Methods: The depth of focus for an ophthalmic surgical microscope
(LuxOR by Alcon Surgical) was assessed. For the depth of field
testing, the target, which has a calibrated spatial frequency bar pattern
on its surface, is angled at 45° to the surgical microscope objective.
The microscope is set to focus at the midpoint of the target. Images
of the target are captured through the microscope’s ocular and further
processed to extract depth of field information. A profile through the
bar pattern in captured images was extracted and digitally analyzed
to quantify the depth of field. To quantify the depth of field, the
local contrast of the profile is calculated, with contrast calculated by
(Imax –Imin)/(Imax + Imin), where Imax is the local maximum pixel
value and Imin is the local minimum pixel value. A threshold of 20%
contrast was chosen to define the boundaries of the depth of field.
The range of image pixels exceeding this threshold was converted to
a physical distance using the known pixel scale of the images. The
measured depth of field is compared to an empirical perceived depth
of field defined by Berek.
Results: Based on this technique, the depth of field of the microscope
was measured to be 15.90 mm. This value exceeds the depth of field
expected based on the Berek formula.
Conclusions: We have developed a standardized method of capturing
images from a depth of field target through a microscope with
automatic image processing. The resultant calculations provided an
objective measure of the depth of field of a surgical microscope. Our
measures exceeded the depth of field empirical equation originally
developed by Berek in 1927. Improvements in modern lens design
may account for these differences.
Commercial Depth of Field Target
Commercial Relationships: Jim Schwiegerling, Alcon Research
(F); Carl Chancy, Alcon Research (F); Ramon C. Dimalanta, Alcon
Research (E)
Support: Alcon Research, Ltd
Program Number: 1926 Poster Board Number: C0234
Presentation Time: 11:00 AM–12:45 PM
The Difference in Rate of Major Complications in PGY-4
Phacoemulsification Cataract Surgery Performed with the
Sovereign versus Infiniti systems: A 10 year experience at the
University of Arizona
Whitney Smith, Fatimah Gilani, Richard Ober. University of Arizona,
Tucson, AZ.
Purpose: Cataract surgery is one of the cornerstones of
ophthalmic training. The learning curve for resident-performed
phacoemulsification is steep and residents tend to improve with
time. Increased availability of newer technology, including surgical
simulators and phacoemulsification machinery, is commonly believed
to decrease rates of major complications. This study sought to
identify the difference in rate of major complications of PGY-4 level
cataract surgery done with the Sovereign system (AMO, Abbott Park,
IL) versus the Infiniti system (Alcon, Fort Worth, TX).
Methods: A retrospective review was performed of 2506 cataract
cases at the Southern Arizona Veterans Administration Hospital in
Tucson, Arizona. Operative notes were used to identify all cases from
July 2001 to June 2011 where a PGY-4 resident was the primary
surgeon. Major complications were defined as posterior capsular
disruption, vitreous loss, and retained lens fragments. The Sovereign
phacoemulsification system was used from July 2001 to June 2007 on
1308 cases by 12 residents and the Inifiniti system was used on 1198
cases from July 2007 to June 2011 by 11 residents.
Results: There was no statistically significant difference between the
rate of major complications with the Sovereign (5.6%) or Inifiniti
(6.6%) phacoemulsification systems (p=0.038). Rates of posterior
capsular disruption and retained lens fragments were slightly higher
with the Sovereign system (4.5% and 3.8%) than with the Inifiniti
system (3.6% and 2.7%, respectively), while the rate of vitreous loss
©2015, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
to reproduce any abstract, contact the ARVO Office at pubs@arvo.org.
ARVO 2015 Annual Meeting Abstracts
was higher with the Inifiniti system (3.3%) than with the Sovereign
(3.0%). None of these results were statistically significant (p=0.021,
0.045, 0.018).
Conclusions: The rate of major complications from PGY-4
resident-performed phacoemulsification surgery did not depend
on the phacoemulsification system used. Residents can gain
experience through performing cases or through a simulated surgery
environment. Further studies are needed to determine the optimal
balance between surgical experience and surgical simulation for
resident training.
and percentage of cells showing αSMA expression were counted.
Differences between groups were evaluated using Wilcoxon ranksum tests and analyses of variance (ANOVA) with Games-Howell
post-hoc analyses.
Results: Compared to controls, lenses filled with nanogel show
less severe CO formation, indicated by a smaller αSMA expression
(P=0.004). Microscopic images show differences in morphological
cell response between the nanogel refilled groups. αSMA expression
was highest in lenses refilled with nanogel alone (9.54±11.29%). The
cell number for the nanogel without peptides group was significantly
lower compared to almost all groups (P values ≤0.013) except for the
groups with the two fibronectin-derived peptides (P=0.167) and the
two laminin-derived peptides (P=0.530).
Conclusions: Our results show that LEC respond to both
the presence of nanogels and the incorporation of peptides.
Nanomaterials targeting biological pathways, in our case interactions
with adhesion molecules, can be promising for CO prevention.
However, further research is needed to discover optimal nanogel/
peptide combinations.
Commercial Relationships: Lisanne Nibourg, None; Edith
Gelens, Nano Fiber Matrices B.V. (E); Menno D. Jong, Nano Fiber
Matrices B.V. (E), Nano Fiber Matrices B.V. (I); Theo V. Kooten,
None; Steven Koopmans, None
Support: European Fund for Regional Development and
Samenwerkingsverband Noord-Nederland
Commercial Relationships: Whitney Smith, None; Fatimah
Gilani, None; Richard Ober, None
Program Number: 1927 Poster Board Number: C0235
Presentation Time: 11:00 AM–12:45 PM
Nanofiber-based hydrogels for the prevention of capsular
opacification
Lisanne Nibourg1, 2, Edith Gelens3, Menno D. Jong3, Theo V. Kooten4,
Steven Koopmans1. 1Ophthalmology, University Medical Center
Groningen, University of Groningen, Groningen, Netherlands;
2
Laboratory for Experimental Ophthalmology, University Medical
Center Groningen, University of Groningen, Groningen, Netherlands;
3
Nano Fiber Matrices B.V., Groningen, Netherlands; 4Biomedical
Engineering, University Medical Center Groningen, University of
Groningen, Groningen, Netherlands.
Purpose: Knowledge of the biological processes underlying
formation of capsular opacification (CO) enables development of new
methods for CO prevention. We performed an experimental study in
which nanofiber-based hydrogels (nanogels) with attached peptides
were used to simulate a more natural extracellular environment for
the lens epithelial cells (LECs) in order to prevent CO in a porcine
eye model.
Methods: Fresh natural porcine (Sus domesticus) eyes were obtained
from the local slaughterhouse. The lens content was removed and
the empty capsules were refilled with nanogel. The lenses were
divided into 14 groups (N=4 per group), refilled with nanogel without
peptides and nanogels with 13 combinations of 5 different peptides:
two laminin-derived, two fibronectin-derived, and one collagen IVderived peptide. A control group of 4 lenses was refilled with sodium
hyaluronate. After refilling, lenses were extracted and cultured
for three weeks. The lenses were fixated with paraformadehyde,
and LECs were stained with phalloidin and 4’,6-diamidino-2phenylindole, after which the complete lenses were assessed using
confocal laser scanning microscopy (CLSM). Next the capsules were
separated from the lens content and stained for alpha smooth muscle
actin (αSMA), again followed by CLSM. Total number of cells
©2015, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
to reproduce any abstract, contact the ARVO Office at pubs@arvo.org.