The effect of lens edge design versus anterior capsule overlap on posterior capsule opacification

Development and Validation of a Prediction Model for Nd:YAG Laser Capsulotomy: A Retrospective Cohort Study of 9768 eyes

INTRODUCTION

Posterior capsular opacification (PCO) is the most common complication of cataract surgery. In this study, we develop a model to quantitatively predict the probability of Nd:YAG laser capsulotomy for vision-threatening PCO to improve the life quality of postoperative patients.

METHODS

A registry analysis of cataract procedures performed between the years 2010 and 2021. Following the screening of 16,802 patients (25,883 eyes), 9768 patients (eyes) were enrolled. The cohort was randomly divided into two groups: training (n = 6838) and validation (n = 2930). To identify relevant risk factors, univariate, multivariate, and Least Absolute Shrinkage and Selection Operator (LASSO) algorithm Cox regression analysis were employed, and a nomogram was created to demonstrate the prediction result.

RESULTS

At 5 years, the overall cumulative incidence of Nd:YAG laser capsulotomy was 12.0% (1169/9768). The following variables were included in the prediction model: sex [hazard ratio (HR) = 1.53, 95% CI 1.32-1.76], age (HR = 0.71, 95% CI 0.56-0.88), intraocular lens (IOL) material (HR = 2.65, 95% CI 2.17-3.24), high myopia (HR = 2.28, 95% CI 1.90-2.75), and fibrinogen (HR = 0.79, 95% CI 0.72-0.88). In the validation cohort, the area under the curve (AUC) of 1-, 3-, and 5-year predictions for Nd:YAG laser capsulotomy were 0.702, 0.691, and 0.688, respectively. For a subgroup of patients with high myopia, the protective effect of hydrophobic IOL disappeared (HR = 0.68, 95% CI 0.51-1.12, P = 0.127).

CONCLUSION

This model could predict the probability of Nd:YAG laser capsulotomy for vision-threatening PCO after cataract surgery by taking into account factors such as age, gender, IOL material, high myopia, and fibrinogen. Meanwhile, implantation of a hydrophobic IOL in individuals with high myopia did not demonstrate a protective impact against vision-threatening PCO.

Multiple linear regression model for improving accuracy of capsulorhexis size calculation in femtosecond laser-assisted cataract surgery for adults: a retrospective single-center study

BACKGROUND

Differences between programmed capsulorhexis diameter and actual resulting capsulorhexis diameter (ARCD) are commonly encountered in femtosecond laser-assisted cataract surgery (FLACS). The purpose of this study was to identify the preoperative ophthalmic variables influencing capsulorhexis diameter index (CDI) in FLACS for adults and create a multiple linear regression model for obtaining a more accurate capsulorhexis diameter.

METHODS

This retrospective study involved sixty-seven eyes of 44 patients who received FLACS and intraocular lens implantation. The ARCD was measured using anterior segment swept-source optical coherence tomography (CASIA 2). Keratometry (K1, K2 and average K), anterior chamber depth (ACD), lens thickness (LT), anterior chamber width (ACW), white-to-white (WTW), curvature radius of anterior lens capsule (Front R) and axial length (AL) were all measured preoperatively. Based on the derived data, LT/ACW, LT/AL, LT/ACD and LT/ACW/Front R were calculated. The ratio of the programmed capsulorhexis diameter and ARCD was defined as the CDI. Correlation analysis was conducted to examine the relationship between preoperative variables listed above and the CDI. Multiple linear regression analysis was applied to select the most influential preoperative variables on CDI.

RESULTS

ACD, LT, ACW, Front R, AL, LT/ACW, LT/AL, LT/ACD, and LT/ACW/Front R showed significant correlation with CDI. Front R and LT/ACW/Front R were selected as constants in the multiple linear regression model using stepwise variable selection. The following equation represents the multiple linear regression model: CDI = 1.306-4.516 × LT/ACW/FrontR-0.011 × Front R, when P < 0.0001, adjusted R-squared = 0.919, variance inflation factor = 8.389, and Durbin-Watson ratio = 1.846. Predicted postoperative capsulorhexis diameter (PPCD) equation was created based on CDI equation as follows: PPCD = programmed capsulorhexis diameter × 1.306-4.516 × LT/ACW/FrontR-0.011 × Front R.

CONCLUSION

Front R and LT/ACW/Front R were found to be the most significant influencing factors of capsulorhexis size. CDI and PPCD calculation equations presented in this study may be useful in setting up more accurate programmed capsulorhexis diameter for FLACS in adults, resulting in a precise ARCD.

Effects of intraocular lens anterior edge design on anterior capsule morphology changes following femtosecond laser-assisted capsulotomy

PURPOSE

To compare morphological changes in the anterior capsule of two intraocular lenses (IOLs) with different anterior edge designs 6 months after femtosecond laser-assisted capsulotomy surgery (FLACs).

METHODS

This study included 168 eyes from168 patients undergoing FLACs. Group A included 74 eyes from 74 patients who had an Acrysof IQ Restor SN6AD3 IOL implantation with a flat anterior edge and Group B included 94 eyes of 94 patients with a TECNIS Multifocal ZMB00 IOL implantation and a "peak-like" anterior edge. All patients were followed up for 6 months. We assessed anterior capsule morphological changes including variation of anterior opening diameters and lens epithelial cell (LEC) proliferation in four directions, variation of anterior opening area, and the level of anterior capsule opacification (ACO).

RESULTS

Variation of anterior opening diameters in 4 directions were significantly lower in Group B (P < 0.05). Obvious shrinkage ratio of anterior opening diameters and contraction of anterior opening area (P < 0.05) appeared in Group A. LEC proliferation was along the "peak" in Group B, while it spread to the edge of anterior capsule in Group A. ACO grades 6 months after operation in Groups A and B were as follows: grade I in 28.38% and 82.98% of eyes, grade II in 51.35% and 17.02% of eyes, and grade III in 20.27% and 0% of eyes, respectively.

CONCLUSIONS

These findings suggest that a "peak-like" IOL anterior edge design played an important role in maintaining the morphology of anterior capsule in the early postoperative stage.

Dysphotopsias or Unwanted Visual Phenomena after Cataract Surgery

Dysphotopsias are unwanted visual phenomena that occur after cataract surgery. They represent some of the most common reasons for patient dissatisfaction after uncomplicated surgery for cataract phacoemulsification with in-the-bag intraocular lens (IOL) implantation. Depending on the form of the optical phenomenon and the effect it poses on vision, dysphotopsias are divided into positive and negative type. Positive dysphotopsias are usually described by patients as glare, light streaks, starbursts, light arcs, rings, haloes, or flashes of light. Negative dysphotopsias are manifested as an arc-shaped shadow or line usually located in the temporal part of the visual field, similar to a temporal scotoma. In addition to their different clinical manifestations, positive and negative dysphotopsia also have different risk factors. Even though up to 67% of patients may experience positive dysphotopsia immediately after surgery, only 2.2% of the cases have persistent symptoms up to a year postoperatively. Surgical intervention may be indicated in 0.07% of cases. The incidence of negative dysphotopsias is up to 26% of all patients; however, by one year postoperatively, the symptoms usually persist in 0.13 to 3% of patients. For both types of dysphotopsia, preoperative patients' education, accurate preoperative diagnostics, and use of an appropriate IOL design and material is mandatory. Despite all these measures, dysphotopsias may occur, and when noninvasive measures fail to improve symptoms, a surgical approach may be considered.

Spin-Coating-Based Facile Annular Photodynamic Intraocular Lens Fabrication for Efficient and Safer Posterior Capsular Opacification Prevention

Posterior capsular opacification (PCO) is the most common complication after cataract surgery, which is primarily caused by the proliferation of the residual lens epithelial cells (LECs) in the lens capsule. Previous studies have demonstrated that a drug-eluting intraocular lens (IOL), aimed to in situ eliminate LECs, are an effective and promising way to prevent PCO. However, because of the potential toxicities of the antiproliferative drugs to the adjacent tissues, the safety of such drug-eluting IOLs is still a highly important issue to be solved. In this investigation, a facile photodynamic coating-modified IOL was developed for effective and safer PCO prevention. An annular poly(lactide-co-glycolic acid) (PLGA) coating loaded with photosensitizer chlorin e6 (Ce6) was prepared by a spin-coating technique. The optical property investigations showed that the Ce6@PLGA coating was particularly suitable for the IOL surface modification. The in vitro cell culture investigation showed that Ce6@PLGA coating-modified IOLs effectively eliminated LECs when treated with light illumination, whereas it appeared to have good cytocompatibility without irradiation. The investigation of the cell elimination mechanism showed that the apoptosis of HLECs may be associated with the cytomembrane disruption induced by ROS, which is generated by the photodynamic coating during light illumination. The in vivo implantation experiments confirmed the desired PCO prevention effect, as well as the safety to and biocompatibility with the surrounding tissues. Thus, the facile Ce6@PLGA coating will provide an effective yet safe alternative of IOL surface modification for PCO prevention.

Precision pulse capsulotomy: performance metrics and utility in routine and complex cases

PURPOSE

To evaluate precision pulse capsulotomy (PPC) performance.

SETTING

University and private practice in the United States and South Korea.

DESIGN

Multicenter retrospective analysis.

METHODS

The surgical videos of 337 cataract surgeries with PPC capsulotomy performed by 4 surgeons at 4 centers were used to assess capsulotomy outcomes including completion rate, diameter, roundness (ovality), and quality of capsular overlap.

RESULTS

PPC use resulted in 99.4% free-floating capsulotomies from 337 cases. Video image analysis in a subset (n = 52) yielded a mean capsulotomy diameter of 5.0 mm ± 0.16 mm SD (95% CI, 4.96-5.04 mm). Capsulotomies were round to slightly oval at the end of the case with a mean ovality of 3.0% ± 2.86% (95% CI, 2.22%-3.78%; 360 degrees capsular overlap was obtained in 98% of cases. The offset of the capsulotomy center with the intraocular lens (IOL) optic center was 197 μm ± 122 μm (SD) (95% CI, 148-246 μm). PPC was used successfully in traumatic cataracts with compromised anterior and posterior capsule, phacodonesis, intumescent cataract with constricted pupil, and zonular dialysis and in penetrating keratoplasty with open-sky extracapsular cataract extraction.

CONCLUSIONS

Surgeons obtained good PPC capsulotomy outcomes in routine and challenging cases. Little variation was observed in achieving free-floating capsulotomies with approximately 5.0 mm diameter and complete capsular overlap. Variation was observed in the amount of offset between the capsulotomy center and the center of the IOL optic. PPC was useful in cases with multiple comorbidities that challenge capsulotomy performance.

Limbus-centered marking technique-assisted continuous circular capsulorhexis

To introduce a limbus-centered continuous circular capsulorhexis (CCC) marking technique.Compared with traditional capsulotomy diameter mark technique, a self-designed limbus-centered capsulotomy mark (LCM) was used to perform the routine cataract surgery in this observational study. Ten eyes were included in each group. The area outer/inner 5.5-mm CCC ring, the furthest/nearest distance from the capsule margin to the intraocular lens (IOL) margin, the CCC total coverage IOL area were measured and compared between this 2 groups.No significant differences were found for all the comparison parameters between the 2 groups (all P > .05). However, the capsule total coverage area, area inner 5.5-mm ring was lower in the LCM group, which demonstrated advantage of LCM.The limbus-centered capsulotomy diameter mark, as an inexpensive and convenient method, helps to perform limbus-centered capsulorhexis with not only a 360° overlapping capsular edge but also well-centered IOL optics.

Precision pulse capsulotomy: Initial clinical experience in simple and challenging cataract surgery cases

PURPOSE

To evaluate precision pulse capsulotomy (PPC) in simple and challenging cataract surgery cases.

SETTING

Clínica Quesada, San Salvador, El Salvador.

DESIGN

Prospective case series.

METHODS

This single-center prospective study assessed cataract surgeries with anterior capsulotomy performed using a PPC device through a 2.2 mm corneal incision in the presence of an ophthalmic viscosurgical device. This was followed by phacoemulsification and intraocular lens implantation. Outcomes included capsulotomy appearance and diameter, surgical complications, and postoperative visual acuity.

RESULTS

The study comprised 38 eyes. All cases resulted in 360-degree complete, round capsulotomies averaging 5.5 mm in diameter with intracapsular IOL fixation. No PPC-related complications were observed intraoperatively or on follow-up at 3 to 8 months. The PPC was useful in challenging cases with corneal opacities that obscured the capsulotomy path or with poorly dilated pupils. Precision pulse capsulotomy occurs instantaneously everywhere along the capsulotomy path, which allowed safe release of subcapsular pressure in intumescent cataracts with consistent creation of a round, appropriately sized capsulotomy. The PPC edge quality was shown in a case with 6 clock hours of zonular dialysis in which iris hooks held the capsulotomy edge for over 45 minutes for removal of a 4+ cataract.

CONCLUSIONS

Precision pulse capsulotomy had a short learning curve and was integrated seamlessly into the surgical routine. The combination of suction with ultrafast capsulotomy provided capsulotomy roundness, sizing, safety, and edge quality that significantly facilitated difficult cases. The ease of use, consistency, and efficiency of PPC capsulotomy might support its use under many practice scenarios.

Intraindividual comparison of capsule behavior of 2 hydrophobic acrylic intraocular lenses during a 5-year follow-up

PURPOSE

To evaluate and compare the 5-year postoperative anterior (ACO) and posterior capsule opacification (PCO), the occurrence of glistenings, and the level of anterior capsule retraction after implantation of 2 designs of 1-piece hydrophobic acrylic IOLs.

SETTING

Hospital St. John, Vienna, Austria.

DESIGN

Randomized controlled prospective case series.

METHODS

Patients had an Acrysof SA60AT IOL (Group A) implanted in 1 eye and a Tecnis ZCB00 IOL (Group B) implanted in the fellow eye. At 1, 3, and 5 years, the PCO level was evaluated with the Evaluation of Posterior Capsule Opacification software. The level of ACO and capsule retraction was graded subjectively. Glistenings were scored as present or not present.

RESULTS

Fifty eyes of 25 patients were evaluated after 5 years. No significant differences in PCO scores were found between the 2 groups at all follow-up visits (1 year: 0.06 ± 0.12 [SD] versus 0.07 ± 0.13, P = .35; 3 years: 0.23 ± 0.36 versus 0.22 ± 0.32, P = .66; 5 years: 0.36 ± 0.41 versus 0.36 ± 0.54, P = .98). A significant increase in PCO score was found between 3 and 5 years (P < .01). Anterior capsule opacification was present in Group A and Group B in 18.0% and 2.7% of eyes (P = .03), in 92.0% and 24.0% of eyes, and in 100% and 52% of eyes (P < .01) at 1, 3, and 5 years, respectively. Glistenings (5 years 100%) were observed in Group A.

CONCLUSION

Both IOLs had a comparable PCO rate 5 years after surgery, although more ACO and retraction as well as glistenings were observed in Group A.

Comparison of Manual Capsulorhexis and 25-Gauge Vitrectorhexis in Pediatric Cataract Surgery: A Pilot Study

PURPOSE

To compare short-term visual outcomes (best corrected visual acuity [BCVA]), visual axis opacification, anterior (ACCC) and posterior (PCCC) continuous curvilinear capsulorhexis size, shape, and extension, and their decentration between manual capsulorhexis and 25-gauge vitrectorhexis in pediatric cataract surgery with intraocular lens (IOL) implantation.

METHODS

Thirty eyes of children aged 3 to 8 years with developmental cataract were randomly selected for ACCC and PCCC by manual capsulorhexis forceps and 25-gauge vitrectomy cutter followed by IOL implantation and limited anterior vitrectomy. The size of the ACCC and PCCC was measured intraoperatively with calibrated capsulorhexis forceps. Patients were followed up for 3 months postoperatively and were evaluated for BCVA and visual axis opacification. Slit-lamp photographs of operated eyes were taken in retroillumination. The size in millimeters and decentration of the ACCC and PCCC from the center of the IOL were measured with the help of the Python imaging library.

RESULTS

There was no statistically significant difference between BCVA (P > .05), visual axis opacification (P > .05), size of the ACCC (P > .05) and its decentration (P > .05), extension of the rhexis (P > .05), and size of the PCCC (P > .05) and its decentration (P > .05) between the two methods.

CONCLUSIONS

In both groups, BCVA, visual axis opacification, and ACCC and PCCC size, shape, and decentration from the center of the IOL were comparable, making 25-gauge vitrectorhexis a good alternative to manual capsulorhexis. [J Pediatr Ophthalmol Strabismus. 2019;56(5):327-332.].

Clinical performance in continuous curvilinear capsulorhexis creation supported by a digital image guidance system

PURPOSE

To test whether a default capsulorhexis diameter could be attained more precisely when manual continuous curvilinear capsulorhexis (CCC) creation was supported by a biomorphological detection unit.

SETTING

Ruhr University Eye Hospital, Bochum, Germany.

DESIGN

Prospective interventional study.

METHODS

Patients were assigned to either of 2 groups. In the first group, a digital image system was applied to guide capsulorhexis. In the second group, the CCC was created without digital support. Postoperatively, horizontal and vertical capsulorhexis dimensions were measured. A set target diameter of 5.5 mm was compared with intraoperative and postoperative CCC diameters, which were also compared with each other. The number of eyes with postoperative CCC diameters outside the reference range of 4.5 to 6.0 mm was assessed.

RESULTS

In 427 eyes, the capsulorhexis size was assessed. Digital image guidance was applied in 203 eyes. Intraoperatively, horizontal capsulorhexis diameters created with surgical guidance differed significantly less from the target diameter than in the control group (P < .001). Eyes treated with surgical guidance differed significantly less from the target diameter (P < .001). Analogously, vertical capsulorhexis diameters differed significantly less from the target when digital support was used, intraoperatively and postoperatively (P < .001). In 418 eyes, postoperative diameters were significantly larger than intraoperatively in both directions (P < .001). Vertical CCC diameters were more frequently within the reference range intraoperatively and postoperatively with surgical guidance (P = .009). Horizontally, eye tracking showed accordance with the target diameter in 87.6% (controls: 91.7%).

CONCLUSION

Intraoperative image guidance facilitated CCC creation significantly during standard phacoemulsification.

An Optical Section-Assisted In Vivo Rabbit Model for Capsular Bend and Posterior Capsule Opacification Investigation

Purpose

To establish an optical section-assisted in vivo rabbit model for capsular bend and posterior capsule opacification (PCO) investigation.

Methods

A total of 10 rabbits underwent phacoemulsification surgery and intraocular lens (IOL) implantation. On the basis of the relationship between the anterior capsule and IOL, the rabbits were divided into complete overlap and incomplete overlap groups, in which six and four rabbits were included, respectively. The capsular bend optical sections were assessed using ultra-long scan depth optical coherence tomography (UL-OCT), and posterior capsule opacification was evaluated with slit lamp on postoperative day 3, 7, 14, and 28. In addition, histopathological section was used to verify the accuracy of capsular bend type captured by OCT in three rabbits.

Results

Based on the special animal model, six capsular bend types were observed, namely, anterior (A), middle (M), posterior (P), detachment (D), funnel (Fun) and furcate adhesion (Fur). On day 3, capsular bend began to form. On 14 days, the capsular bends were comprised of A, M and D types, which were almost maintained until day 28. Histopathological section findings were consistent with optical sectioning results. In the incomplete and complete groups, the earliest PCO within the optical zone were on day 7 and 28, respectively. The incomplete group exhibited higher incidence and faster PCO on day 7 (p = 0.038) and 14 (p = 0.002).

Conclusions

This animal model not only mimics capsular bend evolution and PCO processes but also produces OCT optical section images equivalent to and more repeatable than histopathology, thereby providing a promising method for the further investigations of PCO.

The effect of single-piece hydrophobic acrylic intraocular lenses on the development of posterior capsule opacification

PURPOSE

To evaluate the long-term effect of a single-piece hydrophobic acrylic intraocular lens (IOL), AcrySof SN60AT (Alcon Laboratories, Fort Worth, Texas, USA), on the development of posterior capsule opacification (PCO) 5 years postoperatively.

DESIGN

Prospective, observational, consecutive, case series.

METHODS

setting: Iladevi Cataract and IOL Research Center, Ahmedabad, India.

STUDY POPULATION

Three hundred and ninety eyes with uncomplicated age-related cataract were included. Patients with diabetes mellitus, glaucoma, high myopia, pseudoexfoliation, traumatic cataract, subluxated cataract, previous ocular surgeries, and allergy to dilating drops were excluded. intervention procedures: Digital retroillumination photographic documentation was performed and analyzed for PCO using Evaluation of Posterior Capsule Opacification software. The scores and areas were calculated.

MAIN OUTCOME MEASURES

PCO development and the influence of the anterior capsule cover (total on and part on) on the IOL optic was studied within the capsulorrhexis margin and the central 3.0 mm optic area.

RESULTS

There was a significant increase in PCO up to 3 years. No significant change in PCO was observed between 3 and 5 years within the capsulorrhexis margin and central 3.0 mm optic area. In the total on group, within the capsulorrhexis margin, significantly lower scores and areas were observed when compared with part-on scores and areas.

CONCLUSION

The increase in PCO up to 3 years was significant. Stabilization in PCO was observed between 3 and 5 years with no difference at 5 years. There was a low incidence of PCO in eyes with total anterior capsule cover over the IOL optic.

Open ring-shaped guider for circular continuous curvilinear capsulorhexis during cataract surgery

We describe a new type of open-loop caliper for capsulorhexis during cataract surgery. This tool, which is made of poly(methyl methacrylate), can optimize capsulorhexis shape, size, and centration. One of the strengths of this tool, which derives from the open-loop design, is its ease of insertion and removal via a small incision site compared with other calipers used for capsulorhexis. The caliper is positioned on the anterior capsule after the anterior chamber is filled with an ophthalmic viscosurgical device and removed after creation of the continuous curvilinear capsulorhexis. The caliper enables the surgeon to achieve an ideal capsulorhexis and promotes long-lasting circularity.

FINANCIAL DISCLOSURE

Dr. Joo is one of the inventors on the patent filed by the Catholic University of Korea covering details in this manuscript. Dr. Lee has no financial or proprietary interest in any material or method mentioned.

Intraindividual comparative analysis of capsule opacification after implantation of 2 single-piece hydrophobic acrylic intraocular lenses models: Three-year follow-up

PURPOSE

To compare the 3-year postoperative anterior (ACO) and posterior (PCO) capsule opacification and the level of anterior capsule retraction after implantation of 2 single-piece hydrophobic acrylic intraocular lens (IOL) models.

SETTING

Hospital of St. John of God, Vienna, Austria.

DESIGN

Comparative randomized controlled double-blind clinical trial.

METHODS

Eyes with bilateral cataract were evaluated. Each patient had an Acrysof SA60AT (interrupted optic edge) IOL implanted in 1 eye (Group A) and a Tecnis ZCB00 (continuous optic edge) IOL implanted in the fellow eye (Group B). One and 3 years postoperatively, PCO was evaluated using Evaluation of Posterior Capsule Opacification software and the ACO level and capsule-retraction level were evaluated and graded subjectively.

RESULTS

The study evaluated 100 eyes of 50 patients ranging from 61 to 80 years. Postoperatively, there were no statistically significant differences in PCO between Group A and Group B at 1 year (0.06 ± 0.12 [SD] and 0.07 ± 0.13, respectively; P = 4.35) or 3 years (0.23 ± 0.36 and 0.22 ± 0.32, respectively; P = .66). In Group A and Group B, ACO was present in 18.0% of eyes and 2.7% of eyes, respectively, at 1 year (P = .03) and in 92.0% and 24.0%, respectively, at 3 years (P < .01). Capsule phimosis (18.0% at 1 year; 30.0% at 3 years) and glistenings (66.0% at 1 year; 86.0% at 3 years) were observed in Group A only.

CONCLUSION

Both IOLs had similarly low PCO rates 3 years postoperatively, although more ACO and capsule retraction were observed in eyes with the interrupted optic edge IOL.

Femtosecond-laser assisted cataract surgery: a review

Introduced in 2008, the femtosecond laser is a promising new technological advance which plays an ever increasing role in cataract surgery where it automates the three main surgical steps: corneal incision, capsulotomy and lens fragmentation. The proven advantages over manual surgery are: a better quality of incision with reduced induced astigmatism; increased reliability and reproducibility of the capsulotomy with increased stability of the implanted lens; a reduction in the use of ultrasound. Regarding refractive results or safety, however, no prospective randomized study to date has shown significant superiority compared with standard manual technique. The significant extra cost generated by this laser, undertaken by the patient, is a limiting factor for both its use and study. This review outlines the potential benefits of femtosecond-laser-assisted cataract surgery due to the automation of key steps and the safety of this new technology.

The effect of femtosecond laser capsulotomy on the development of posterior capsule opacification

PURPOSE

To evaluate and compare the effects of femtosecond laser-assisted anterior capsulotomy and manual anterior capsulorhexis on posterior capsule opacification (PCO) development.

METHODS

Femtosecond laser-assisted anterior capsulotomy was performed in 40 eyes of 40 patients (FS group) and manual anterior capsulorhexis was performed in 39 eyes of 39 patients (CCC group). An AcrySof one-piece hydrophobic acrylic intraocular lens (Alcon Laboratories, Inc., Fort Worth, TX) was implanted in all eyes. The PCO level was measured using Open-Access Systematic Capsule Assessment (OSCA) software 18 to 26 months after surgery. Postoperative intraocular lens position (ie, tilt and decentration) was measured using Scheimpflug images (Pentacam; Oculus Optikgeräte GmbH, Wetzlar, Germany).

RESULTS

There was no statistically significant difference in age, axial length, and follow-up time between the two groups (P > .05). Vertical tilt, horizontal and total decentration of intraocular lenses, and PCO proved to be significantly higher in the CCC group (P = .03, .04, .03, and .01, respectively). After adjusting for axial length and follow-up time, manual anterior capsulorhexis was found to be a significant predictor of higher PCO scores in the multivariable regression model (β: 0.33; 95% CI: 0.01 to 0.65; P = .04). Vertical tilt affected PCO scores after adjusting for axial length and follow-up time (β: 0.07; 95% CI: 0.01 to 0.12; P = .02). No capsulotomies were performed during follow-up in either group.

CONCLUSIONS

Femtosecond laser-assisted anterior capsulotomy proved to be a safe procedure for postoperative PCO rates. Due to better intraocular lens position, femtosecond laser-assisted anterior capsulotomy resulted in slightly decreased PCO scores; however, evaluating its clinical significance requires further studies.

Negative dysphotopsia: the enigmatic penumbra

PURPOSE

To determine the cause of negative dysphotopsia and the location, appearance, and relative intensity of such images in pseudophakic eyes.

SETTING

Baylor College of Medicine, Houston, Texas, USA.

DESIGN

Reporting available data addressing a specific clinical question.

METHODS

Negative dysphotopsia was simulated using the Zemax optical design program. The nominal values for the pseudophakic eye model were as follows: IOL power, 20.0 diopters (D); corneal power, 43.5 D; Q value, -0.26; axial IOL depth behind pupil, 0.5 mm; external anterior chamber depth (corneal vertex to iris plane), 4.0 mm; optic diameter, 6.0 mm; pupil diameter, 2.5 mm.

RESULTS

From the first ray-tracing simulation, analysis of the image for the nominal parameters showed 2 annuli (ring-shaped) shadows. The inner annulus shadow was located from a retinal visual field angle of 86.0 to 100.0 degrees (width 14.0 degrees), and the outer annular shadow was located from 105.9 to 123.3 degrees (width 17.4 degrees). Superimposing the inner annulus on the human visual field showed that the shadow would be apparent only temporally, where it is within the limits of the visual field and functional retina. The patient would perceive this as a temporal dark crescent-shaped partial shadow (penumbra).

CONCLUSIONS

Primary optical factors required for negative dysphotopsia are a small pupil, a distance behind the pupil of 0.06 mm or more and 1.23 mm or less for acrylic, a sharp-edged design, and functional nasal retina that extends anterior to the shadow. Secondary factors include a high index of refraction optic material, angle α, and the nasal location of the pupil relative to the eye's optical axis.

FINANCIAL DISCLOSURE

Drs. Zhao and Reisin are employees of and Dr. Holladay is a consultant to Abbott Medical Optics, Inc. No author has a financial or proprietary interest in any material or method mentioned.

Evaluation of Posterior Capsular Opacification following Phacoemulsification, Extracapsular and Small Incision Cataract Surgery

BACKGROUND

Posterior capsular opacification is the most common complication of modern cataract surgery.

METHODS

A prospective study was conducted on 150 patients (150 eyes) out of which 50 eyes each underwent cataract surgery by extracapsular cataract extraction, small incision cataract surgery and phacoemulsification technique. On postoperative follow up posterior capsular opacification and Neodymium: Yttrium Aluminium Garnet laser capsulotomy rate was evaluated.

RESULT

Posterior capsular opacification rate was significantly less (p=0.03) in eyes which had undergone phacoemulsification as compared to extracapsular cataract extraction. However capsulotomy rate was not statistically significant after comparison of the three surgical techniques of cataract surgery.

CONCLUSION

Posterior capsular opacification following cataract surgery can be minimized by the use of small incision cataract surgery and phacoemulsification.

Pathology of 157 human cadaver eyes with round-edged or modern square-edged silicone intraocular lenses: analyses of capsule bag opacification

PURPOSE

To assess the degree of capsular bag opacification in human cadaver eyes with silicone intraocular lenses (IOLs), specifically comparing the differences between round-edged IOLs and modern square-edged IOLs.

SETTING

John A. Moran Eye Center, University of Utah, USA.

DESIGN

Experimental study.

METHODS

The eyes were immersed in 10% formalin on enucleation. They had anterior segment scanning with a very-high-frequency ultrasound (Artemis). After the eyes were sectioned at the equator, gross examination of the anterior segment was performed from the posterior aspect to assess the degree of capsular bag opacification, coverage of the IOL edge by the anterior capsule, and IOL fixation. Selected eyes also had histopathologic examination.

RESULTS

Eighty-seven eyes with a 3-piece round-edged IOL, 43 with a 3-piece square-edged IOL, 26 with a 1-piece plate IOL, and 1 with an accommodating IOL design were included in the analyses of capsular bag opacification. Comparison between 3-piece round-edged IOLs and square-edged IOLs showed statistically significant differences in central posterior capsule opacification (PCO) (P=.0001687) and peripheral PCO (P<.0001). In eyes with square-edged IOLs, PCO had a tendency to start in areas without capsulorhexis coverage of the optic. Twenty-one of 26 eyes with a silicone plate IOL had a neodymium:YAG posterior capsulotomy for dense PCO.

CONCLUSIONS

This first study using pseudophakic human cadaver eyes that includes a significant number of modern 3-piece silicone IOLs with square optic edges confirmed the role of this design in the prevention of PCO.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Factors contributing to posterior capsule opacification following 23-gauge transconjunctival phacovitrectomy

BACKGROUND AND OBJECTIVE

To determine posterior capsule opacification (PCO) rate and identify contributory factors in a series of patients undergoing combined 23-gauge transconjunctival phacovitrectomy.

PATIENTS AND METHODS

Retrospective data on 221 consecutive patients operated on by a single senior surgeon using a standard technique were collected and subjected to univariate analysis with chi-square tests and multivariate analysis with logistic regression.

RESULTS

PCO developed in 46 of 221 cases (20.8%). Major risk factors were: rhegmatogenous retinal detachment (relative risk = 3.3, P = .002), axial length greater than 24.5 mm (relative risk = 2.0, P = .093), intraoperative/postoperative complications (relative risk = 3.3, P = .04), C2F6 tamponade (versus SF6/air) (relative risk = 2.8, P = .01), and postoperative posturing (relative risk = 4.1, P < .001). Multiple logistic regression analysis showed the latter two to be most important.

CONCLUSION

PCO rate following 23-gauge phacovitrectomy is lower than most rates reported for 20-gauge phacovitrectomy. Using shorter-acting gas tamponade and avoiding postoperative posturing may help lower PCO rates.

Pathology of 219 human cadaver eyes with 1-piece or 3-piece hydrophobic acrylic intraocular lenses: capsular bag opacification and sites of square-edged barrier breach

PURPOSE

To assess capsular bag opacification and sites of initial posterior capsule opacification (PCO) in human cadaver eyes with square-edged 1-piece or 3-piece hydrophobic acrylic intraocular lenses (IOLs).

SETTING

John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.

DESIGN

Experimental study.

METHODS

Eyes were immersed in 10% formalin after enucleation and had anterior segment scanning with very-high-frequency ultrasound (Artemis). After the eyes were sectioned at the equator, gross examination of the anterior segment was performed from the posterior aspect to assess capsular bag opacification, anterior capsule coverage of the IOL edge, and IOL fixation. Selected eyes had histopathologic examination.

RESULTS

One hundred nineteen eyes with 1-piece IOLs and 100 with 3-piece IOLs were included in the analyses of capsular bag opacification. There was no difference in central (P=.29) or peripheral (P=.76) PCO. In 63 of 84 eyes with a 1-piece IOL and peripheral PCO, the optic-haptic junction was the site of initiation. In eyes with a 3-piece IOL, initial peripheral PCO was observed at nearly the same rate whether there was full 360-degree anterior capsulorhexis overlap of the optic or no overlap (P=.13). In the latter, the site of PCO initiation was in areas lacking capsulorhexis coverage in 46% of eyes.

CONCLUSIONS

There was no difference in central or peripheral PCO between 1-piece and 3-piece hydrophobic acrylic IOLs. With 1-piece IOLs, PCO tended to start at the optic-haptic junctions. With 3-piece IOLs, full anterior capsule coverage did not produce a statistically significant benefit with respect to PCO prevention.

Anterior capsule relaxing incisions with neodymium:YAG laser for patients at high-risk for anterior capsule contraction

PURPOSE

To examine the effect of anterior capsule relaxing incisions created with a neodymium:YAG (Nd:YAG) laser on prevention of anterior capsule contraction after cataract surgery in high-risk patients.

SETTING

Hayashi Eye Hospital, Fukuoka, Japan.

DESIGN

Randomized masked clinical trials.

METHODS

Patients at high risk for anterior capsule contraction had anterior capsule relaxing incisions in either eye 3 days postoperatively. The anterior capsule opening was measured using a Scheimpflug videophotography system (EAS-1000) immediately and 1, 3, and 6 months after capsulotomy, and the percentage reduction in area was calculated. The degree of intraocular lens (IOL) decentration and tilt, posterior capsule opacification (PCO), and other complications were also assessed.

RESULTS

Of the 84 patients included, 30 had primary angle closure, 28 had pseudoexfoliation, and 26 had diabetic retinopathy. There was no significant difference in the mean opening area between fellow eyes at baseline. In patients with primary angle closure, the area was significantly greater and the percentage reduction in area was significantly less in the capsulotomy group than in the no-capsulotomy group (P≤.0428). In patients with pseudoexfoliation or diabetic retinopathy, the percentage reduction was significantly less in the capsulotomy group than in the no-capsulotomy group (P≤.0493), although there was no significant difference in area. No significant difference was found in IOL decentration or tilt, PCO, or incidence of other complications.

CONCLUSION

Neodymium:YAG laser anterior capsule relaxing incisions in the early period after cataract surgery were effective in preventing anterior capsule contraction in high-risk patients and had no adverse effects.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Complications of cataract surgery

Modern cataract surgery is safe in more than 95 per cent of patients. In the small number of cases where a serious complication occurs, the most common is an intra-operative posterior capsular rupture. This can lead to vitreous loss or a dropped nucleus and can increase the risk of post-operative cystoid macular oedema or retinal detachment. Post-operatively, posterior capsular opacification is the most common complication and can be readily treated with a YAG capsulotomy. The most devastating complication is endophthalmitis, the rate of which is now significantly decreased through the use of intracameral antibiotics. As a clinician, the most important step is to assess the patient pre-operatively to predict higher risk individuals and to counsel them appropriately. In these patients, various pre- or intra-operative management steps can be taken in addition to routine phacoemulsification to optimise their visual outcome.

Satisfaction and dysphotopsia in the pseudophakic patient

OBJECTIVE

To examine factors that influence satisfaction after uncomplicated cataract surgery.

DESIGN

Retrospective case review and examination of patients.

PARTICIPANTS

Sixty-one consecutive patients, seen at the John A. Moran Eye Center, University of Utah School of Medicine, who had uncomplicated cataract surgery from 1 practice and 40 consecutive control patients who met the inclusion criteria and were willing to participate.

METHODS

Inclusion criteria were best-corrected visual acuity (BCVA) of at least 20/20, without any ocular disease that might affect vision. Patients were given a complete ophthalmic examination, had photos of the intraocular lens (IOL) and capsule taken, and were asked questions about dysphotopsia and satisfaction. A group of patients >65 years old with 20/20 BCVA and without other ophthalmic diagnoses were recruited, asked the same questions, and compared.

RESULTS

The only significant correlation with dissatisfaction was dysphotopsia (r = 0.602, CI 0.42-0.74, p < 0.0001). BCVA, uncorrected visual acuity, posterior capsular opacification, and anterior capsule overlap of the optic were not significantly correlated. The IOL patients were significantly worse for reported glare (p < 0.0001), photophobia (p < 0.0001), and flashes of light (p = 0.0002), but not for halos.

CONCLUSIONS

While satisfaction with cataract removal and IOL placement is high, dysphotopsia is the most important contributor to dissatisfaction and is relatively common. Furthermore, these symptoms are much worse than in age-matched controls. Research seeking to ameliorate dysphotopsia is clinically important.

Posterior capsule opacification

Posterior Capsule Opacification (PCO) is the most common complication of cataract surgery. At present the only means of treating cataract is by surgical intervention, and this initially restores high visual quality. Unfortunately, PCO develops in a significant proportion of patients to such an extent that a secondary loss of vision occurs. A modern cataract operation generates a capsular bag, which comprises a proportion of the anterior and the entire posterior capsule. The bag remains in situ, partitions the aqueous and vitreous humours, and in the majority of cases, houses an intraocular lens. The production of a capsular bag following surgery permits a free passage of light along the visual axis through the transparent intraocular lens and thin acellular posterior capsule. However, on the remaining anterior capsule, lens epithelial cells stubbornly reside despite enduring the rigours of surgical trauma. This resilient group of cells then begin to re-colonise the denuded regions of the anterior capsule, encroach onto the intraocular lens surface, occupy regions of the outer anterior capsule and most importantly of all begin to colonise the previously cell-free posterior capsule. Cells continue to divide, begin to cover the posterior capsule and can ultimately encroach on the visual axis resulting in changes to the matrix and cell organization that can give rise to light scatter. This review will describe the biological mechanisms driving PCO progression and discuss the influence of IOL design, surgical techniques and putative drug therapies in regulating the rate and severity of PCO.

Prevention of anterior capsule contraction by anterior capsule relaxing incisions with neodymium:yttrium-aluminum-garnet laser

PURPOSE

To examine the effect of two or three neodymium:yttrium-aluminum-garnet (Nd:YAG) laser relaxing incisions made in the anterior capsular rim on prevention of anterior capsule contraction after cataract surgery.

DESIGN

Randomized clinical trials.

METHODS

One hundred patients scheduled for bilateral cataract surgery were randomized to one of two groups: two or three relaxing incisions in the left eye and no incisions in the right eye, and relaxing incisions in the right eye and no incisions in the left eye. The anterior capsule opening area was measured using Scheimpflug photography immediately after capsulotomy and at one, three, and six months after capsulotomy, and the percentage reduction was calculated. The degree of intraocular lens (IOL) decentration and tilt and of posterior capsule opacification (PCO) also were examined.

RESULTS

There was no significant difference in the anterior capsule opening area between fellow eyes at baseline (P > or = .1770). In patients who underwent two incisions, no significant difference was found between fellow eyes in the opening area (P > or = .4098) or in the percentage of reduction (P > or = .8730) throughout follow-up. In patients who underwent three incisions, the opening area in eyes with capsulotomy was significantly greater than that in eyes without capsulotomy (P < or = .0154), and the percentage reduction was significantly smaller in eyes with capsulotomy than in eyes without capsulotomy (P < or = .0016). No significant differences were found in the IOL decentration and tilt, or in PCO.

CONCLUSIONS

Three relaxing incisions made in the anterior capsule decrease the anterior capsule contraction, whereas two incisions do not.

The Relationship between the Adhesion Characteristics of Acrylic Intraocular Lens Materials and Posterior Capsule Opacification

PURPOSE

To investigate the relationship between the adhesion characteristics of similarly designed hydrophobic acrylic intraocular lenses (IOLs) and posterior capsule opacification (PCO).

METHODS

Three similarly shaped hydrophobic acrylic IOLs with a sharp-edged optic were used. Adhesive force of IOLs was measured with a tackiness tester. Human lens epithelial cells (LECs) were grown on each IOL for 48 h. LECs were then stained with crystal violet, which served as an index of the amount of cells attached to IOLs. Cellular migration and proliferation assays were performed using chamber inserts containing a collagen membrane. After 96 h of incubation, the collagen membranes were stained with hematoxylin and eosin for analysis. Three similarly shaped IOLs were implanted in rabbits. The eyes were enucleated 3 weeks later and analyzed for PCO area.

RESULTS

Hydrophobic acrylic IOLs were classified into three groups: A (less adhesive), B (moderately) and C (highly). The migration area of LECs on the collagen membrane was 5.65 +/- 4.5% in group A, 2.83 +/- 2.1% in group B, and 1.41 +/- 1.5% in group C, with a significant difference between groups A and C (p < 0.05). The mean percentage area of PCO in the rabbit eye was 19.4 +/- 16.7% in group A, 17.5 +/- 8.5% in group B, and 5.5 +/- 3.8% in group C, with a significant difference between groups A and C (p < 0.05).

CONCLUSION

Adhesive force of hydrophobic acrylic IOLs may play an important role in preventing PCO. Among the similarly shaped hydrophobic acrylic IOLs, IOLs of highly adhesive material inhibited LEC migration and PCO more than IOLs of less adhesive material.

Influence on posterior capsule opacification and visual function of intraocular lens optic material

PURPOSE

To examine the influence of optic material on posterior capsule opacification (PCO) by comparing PCO and visual functions between eyes with an acrylic intraocular lens (IOLs) and those with a silicone IOL of the same optic design and with the same haptics.

DESIGN

Randomized clinical trial.

METHODS

One hundred patients scheduled for phacoemulsification surgery underwent implantation of an acrylic IOL (AMO Sensar; AR40e) in one eye and implantation of a silicone IOL (ClariFlex) of the same optic design and loops in the fellow eye. Eighty-nine patients (89%) remained for analysis. The PCO value was measured using the Scheimpflug videophotography system at one, three, six, 12, 18, 24, 30, and 36 months postoperatively. The incidence of eyes that required a neodymium:yttrium-aluminum-garnet (Nd:YAG) laser capsulotomy was examined; visual acuity and contrast sensitivity with and without a glare source were also evaluated.

RESULTS

The mean PCO value did not increase significantly during follow-up in either the acrylic or silicone IOL group. When comparing the groups, no statistically significant difference was found in the PCO or in the incidence of Nd:YAG capsulotomy, although both tended to be slightly better in the silicone group than in the acrylic group. There was also no significant difference between the groups in visual acuity or in photopic and mesopic contrast sensitivity with or without glare.

CONCLUSIONS

When acrylic and silicone IOLs are of the same optic design and with the same haptics, the optic material does not influence the development of PCO enough to impair visual function.

The efficacy of an acrylic intraocular lens surface modified with polyethylene glycol in posterior capsular opacification

To investigate if the surface modification of intraocular lens (IOL) is efficient in the prevention of posterior capsular opacification (PCO), the acrylic surface of intraocular lens (Acrysof) was polymerized with polyethylene glycol (PEG-IOL). The human lens epithelial cells (1 x 10(4) cells/mL) were inoculated on PEG grafted or unmodified acrylic lenses for the control. The adherent cells on each IOL surface were trypsinized and counted. The every PEG-IOL was implanted in 20 New Zealand rabbits after removal of crystalline lens. The formations of PCO were checked serially through retroilluminated digital photography, and the severity scores were calculated using POCOman. The cell adherence patterns on each IOL were examined by scanning electron microscopy. As a result, the mean number of adherent cells of PEG-IOL (3.2+/-1.1 x 10(3)) tended to be smaller than that of the acrylic controls (3.6+/-1.9 x 10(3)) without a statistical significance (p=0.73). However, the mean severity of PCO formation in PEG-IOL was significantly lower than that in the control during the third to sixth weeks after surgery. Scanning electron microscopy revealed that the more patch-like cells were found firmly attached to the IOL surface in control than in the PEG-IOL. Conclusively, PEG polymerization to the acrylic IOL would possibly lessen the formation of PCO after cataract removal.

Three-hundred-sixty degree barrier effect of a square-edged and an enhanced-edge intraocular lens on centripetal lens epithelial cell migration Two-year results

PURPOSE

To study the 360-degree barrier effect of an intraocular lens (IOL) with a square edge at the optic and an enhanced square edge at the optic-haptic junctions (Rayner 570C C-flex) on centripetal migration of lens epithelial cells (LECs) over a 2-year period.

SETTING

Department of Ophthalmology, Scarborough Hospital, Scarborough, United Kingdom.

METHODS

In a prospective study of 40 consecutive eyes, a C-flex IOL was implanted in the bag after phacoemulsification surgery. Eyes with intraoperative complications, requiring additional procedures, without 360-degree overlap of the optic, or with capsule block syndrome were excluded. Follow-up was at 6, 10, 18, and 24 months. At each visit, high-magnification retroillumination digital photographs were taken using a slitlamp-attached digital camera. The barrier effect to LEC migration across the optic edge and the enhanced square edge at the optic-haptic junction was graded as complete (no epithelial pearls or sheet), partial (few epithelial pearls without sheet), and minimal/none (epithelial sheet behind the IOL optic).

RESULTS

Twenty-four patients came to the final follow-up at 24 months. Fifteen of these eyes (63%) had a complete barrier effect throughout the 360 degrees of the IOL. Three eyes (13%) had a partial barrier effect throughout the 360 degrees of the IOL. Three eyes had a complete optic barrier effect but a partial optic-haptic junction barrier effect. Three eyes had a partial optic barrier effect but a complete optic-haptic junction barrier effect. No eye had epithelial sheets extending behind the optic at any location.

CONCLUSIONS

This study showed the barrier effect of the edge design of the C-flex IOL and the efficacy of the enhanced edge in preventing LEC migration at the optic-haptic junction. The enhanced edge was as effective as a sharp square edge in restricting the LEC migration.

Posterior capsule opacification after extra capsular cataract extraction in Indian rural population: foldable acrylic vs poly (methyl-methacrylate) intraocular lenses a randomized clinical trial

PURPOSE

To compare the performance of single-piece acrylic vspoly (methylmethacrylate) intraocular lenses (IOL) on the development of posterior capsule opacification (PCO) after conventional extra capsular cataract extraction (ECCE).

MATERIALS AND METHODS

One hundred and eighty-two eyes of 91 patients with bilateral senile cataract undergoing ECCE were prospectively randomized to receive a single-piece Alcon AcrySof SA60AT IOL or a single-piece EPOCH polymethylmethacrylate IOL in the first eye to have surgery. At 1, 6 and 12 months post-operative follow-up, digital retro illumination images of the posterior capsule were taken for PCO assessment semi-objectively using PCO (POCO automated analysis software) system. Relationship of anterior capsule contact (total off and partial cover) on optic for PCO was analyzed.

RESULTS

The AcrySof IOL was associated with less PCO than EPOCH lens at 6 months (10.01+/-8.75% vs 32.26+/-27.44%; P<0.001) and 1-year (11.65+/-10.55% vs 38.38+/-29.62%; P<0.001) follow-up. The EPOCH IOL showed a remarkably significant difference on development of PCO with anterior capsule overlap on IOL optic (total off and part on) 1 year (P<0.039), whereas no such difference was observed with the AcrySof IOL (P=0.197).

CONCLUSION

The AcrySof IOL led to significantly less PCO than the EPOCH IOL post-operatively after extracapsular cataract extraction.

Ring-shaped caliper for better anterior capsulorhexis sizing and centration

We describe a new type of caliper to optimize the size, shape, and centration of the capsulorhexis during intraocular lens (IOL) surgery. This flexible, ring-shaped tool is positioned on the anterior capsule surface, where it is kept in place by an ophthalmic viscosurgical device. When in place, the caliper provides an ideal guide for the surgeon to follow and facilitates optimal capsulorhexis shape and centration.

Effect of optic material and haptic design on anterior capsule opacification and capsulorrhexis contraction

PURPOSE

To examine the influence of optic material (silicone and hydrophobic acrylic) and haptic design (one-piece and three-piece open loop) of sharp optic edge intraocular lenses (IOL) on anterior capsule opacification (ACO) and capsulorrhexis contraction.

DESIGN

Randomized, controlled, double-blind clinical trial with intraindividual comparison.

METHODS

This study was performed at the Department of Ophthalmology, Medical University of Vienna, Austria, and comprised 210 eyes of 105 patients with bilateral age-related cataract. In group 1 (n = 53 patients), a three-piece acrylic IOL was compared with a three-piece silicone IOL. In group 2 (n = 52 patients), the three-piece acrylic IOL was compared with the one-piece acrylic IOL. One year after the operation, standardized digital slit-lamp images of ACO were taken; 1 week and 1 year after the operation, digital retroillumination images were taken to assess capsulorrhexis size. The intensity of ACO was graded objectively (score, 0% to 100%), and the capsulorrhexis area (square millimeters) was determined objectively.

RESULTS

One year after surgery, the mean ACO score was 21% for the acrylic and 20% for the silicone IOL (P = .4) in group 1 and 18% for both the three-piece and one-piece acrylic IOLs (P = .87) in group 2. Concerning the amount of capsulorrhexis contraction, there was no significant difference between the IOL types that were evaluated in this study (after Bonferroni-Holm correction, P > .05).

CONCLUSION

In the hydrophobic sharp optic edge IOLs that were examined, neither the optic material nor the haptic design had an influence on the amount of ACO or capsulorrhexis contraction.

Posterior capsule opacification

PURPOSE OF REVIEW

This paper assesses the factors that contribute to the formation of an effective capsular bend as a deterrent to posterior capsule opacification. Its goal is to assist the practicing ophthalmologist in separating current understanding of this process from various working models previously proposed.

RECENT FINDINGS

While a square-edge design appreciably improves resistance to posterior capsule opacification, significant factors remain under the control of the surgeon. These factors combine to form the physical and psychological barrier of a capsular bend. Innovative digital imaging has shown lens epithelial cell migration, allowing for a more rapid assessment of posterior capsule opacification resistance. A three-piece intraocular lens allows for full 360 degree capsular bend formation surrounding the optic edge; some single-piece designs may inhibit capsular bend formation. Decreasing, but not eliminating, the surviving lens epithelial cell population may diminish capsular bend strength, which may decrease resistance to posterior capsule opacification in the face of a regenerating cortex. All demographic features of clear/refractive lens exchange suggest higher rates of posterior capsule opacification than with standard cataract surgery.

SUMMARY

The quality of capsular bend formation will determine how resistant an intraocular lens will be to posterior capsule opacification as a consequence of regenerating cortex. As refractive lens exchange and new accommodating intraocular lens designs become more popular, the problems of regenerating cortex will increase in magnitude.

Posterior Capsule Opacification in the Presence of an Intraocular Lens with a Sharp versus Rounded Optic Edge

PURPOSE

To compare the degree of posterior capsule opacification (PCO) and visual function in eyes implanted with an acrylic intraocular lens (IOL) with a sharp posterior optic edge with that in eyes implanted with an IOL with a rounded optic edge.

DESIGN

Randomized clinical trial.

PARTICIPANTS

Seventy-five consecutive patients scheduled for bilateral phacoemulsification were assigned randomly to 1 of 2 groups. One group received an acrylic IOL with a sharp edge (Sensar AR40e, AMO, Santa Ana, CA) in the left eye and an acrylic IOL of the same optic material and loops but with a rounded-edge optic (Sensar AR40) in the right eye. The other group received the sharp-edged IOL in the right eye and the rounded-edge IOL in the left eye. Sixty-nine patients (92%) completed follow-up.

INTERVENTION

All patients underwent implantation of a sharp-edged IOL in 1 eye and a rounded-edge IOL in the fellow eye.

MAIN OUTCOME MEASURES

The PCO value of these patients was measured using the Scheimpflug videophotography system at 1, 3, 6, 12, 18, and 24 months after surgery. The incidence of eyes that required a neodymium:yttrium-aluminum-garnet (Nd:YAG) laser posterior capsulotomy was examined. Visual acuity and contrast sensitivity with and without a glare source also were evaluated.

RESULTS

The mean PCO value in the sharp-edge IOL group was significantly less than that in the rounded-edge IOL group throughout the follow-up period. The incidence of Nd:YAG capsulotomy also was significantly less in the sharp-edge group than in the rounded-edge group (P = 0.0095). No significant difference was found in mean visual acuity during the 24 months of follow-up. However, contrast visual acuity with and without glare was significantly better in the sharp-edge group than in the rounded-edge group at 24 months after surgery.

CONCLUSIONS

The degree of posterior capsule opacification in eyes with an acrylic IOL with a sharp posterior optic edge is significantly less than that in eyes with a rounded-edge IOL, and the sharp-edge optic led to better contrast sensitivity with and without glare.