Anterior capsule relationship of the AcryS of intraocular lens optic and posterior capsule opacification

Influence of Lens Power on IOL/Posterior Lens Capsule Interactions and IOL's PCO Potential

Purpose

Severely myopic eyes have been associated with high posterior capsule opacification (PCO) incidence. Although it has been reported that myopic eyes have weaker or more delayed capsule adhesion than emmetropic eyes, it is unclear whether/how dioptric power and posterior curvature of IOLs affect IOLs' affinity for the posterior lens capsule (PLC) and their PCO potential.

Methods

To investigate this, acrylic foldable IOLs with increasing dioptric power of 6.0D (for high myopia), 20.0D, and 30.0D (for low/non-myopia) were tested on their binding affinity toward PLC and their ability to inhibit the proliferation and infiltration of lens epithelial cells (LECs) using an in vitro simulated human PLC (sPLC) model.

Results

We found that IOL power and posterior radius of curvature (PRC) had significant impacts on IOL/sPLC adhesion forces, which are in the following order: 20.0D ≈ 30.0D > 6.0D. Optical coherence tomography (OCT) images showed that loose binding between 6.0D IOLs and sPLC contributed to larger interface spaces and significantly greater LEC infiltration, proliferation, metabolic activity, and transdifferentiation compared to 20.0D and 30.0D IOLs. Statistical analyses showed that IOLs' PRC may have a substantial influence on IOL/sPLC physical interactions, LEC responses, and PCO incidence.

Conclusions

The overall results suggest that the high PRC of low-diopter (6.0D) IOLs reduces their binding affinity toward the PLC, facilitates LEC reactions, thus causes high PCO incidence in myopic eyes. These findings strongly support that a new design to increase IOL posterior surfaces' PLC affinity may reduce PCO potential and increase safety for myopic patients.

Anterior capsule coverage and rotational stability of an acrylic toric intraocular lens

PURPOSE

To investigate factors related to the rotational stability of an acrylic toric intraocular lens (IOL).

SETTING

Four ophthalmic surgical sites in Japan.

DESIGN

Prospective case series.

METHODS

The study included 120 eyes of 120 patients undergoing phacoemulsification and implantation of a toric IOL (AcrySof IQ, Alcon Laboratories, Inc.). At 1 hour postoperatively, the area of continuous curvilinear capsulorhexis (CCC) was measured, and the state of anterior capsule coverage on the IOL optic (total on or partial on) was recorded. The toric IOL axis orientation was assessed at the end of surgery and at 1 hour, 1 week, 1 month, and 6 months postoperatively. Multiple regression analysis was performed to explore any clinical factors relevant to IOL rotation from the end of surgery to 6 months postoperatively. The explanatory variables included age, anterior chamber depth preoperatively, axial length, type of corneal astigmatism (with-the-rule, against-the-rule, or oblique astigmatism), area of CCC, state of anterior capsule overlap on IOL optic (total coverage vs partial coverage), and surgical sites (surgeons).

RESULTS

The multiple regression analysis in 110 eyes of 110 patients indicated that anterior capsule overlap on the IOL optic was the only variable associated with IOL rotation at 6 months postoperatively (P = .0482). The mean absolute rotation at 6 months was 1.96 ± 1.81 degrees in the total on group and 3.79 ± 3.12 degrees in the partial on group (P = .0004).

CONCLUSIONS

Rotational stability of a single-piece, acrylic toric IOL was better in eyes with total anterior capsule coverage than that in those with partial anterior capsule coverage on the IOL optic.

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.

A prospective evaluation of posterior capsule opacification in eyes with diabetes mellitus: a case-control study

AIM

To compare the development of posterior capsule opacification (PCO) between eyes with and without diabetes mellitus after single-piece hydrophobic acrylic intraocular lens implantation 4 years postoperatively.

METHODS

In this prospective, observational case-control study carried out at Iladevi Cataract and IOL Research Centre, Ahmedabad, India, 75 consecutive eyes with diabetes mellitus (cases) were compared with 75 age-matched eyes with age-related cataract (controls). A detailed, preoperative and posterior segment evaluation was carried out in eyes with diabetes mellitus to detect the presence or absence of diabetic retinopathy (DR). The Mann-Whitney U-test was applied to compare the differences in the development of PCO between the two groups.

RESULTS

There was no difference in median PCO between cases and controls at 1 month (2.0 vs 1.50, P<0.068), but cases had a higher median PCO at 12 months (2.95 vs 1.30, P<0.001). At 4 years, there was no significant difference in median PCO between cases and controls (3.75 vs 2.25, P=0.273). The duration of diabetes increased the incidence of PCO at 4 years (P=0.02). Severity of DR had no influence on the progress of PCO at 4 years (P=0.69).

CONCLUSION

Diabetes mellitus did not increase the incidence of PCO at 4 years. The duration of diabetes increased the risk of PCO. The severity of retinopathy did not influence the development of PCO.

Comparison of posterior capsule opacification with hydrophobic acrylic and hydrophilic acrylic intraocular lenses

PURPOSE

To compare posterior capsule opacification (PCO) 3 years postoperatively in contralateral eyes with a single-piece hydrophobic acrylic and 1 of 2 single-piece hydrophilic acrylic intraocular lenses (IOLs) with different configurations.

SETTING

Iladevi Cataract and IOL Research Institute, Ahmedabad, India.

DESIGN

Prospective randomized clinical trial.

METHODS

A hydrophobic Acrysof (hydrophobic group) or a hydrophilic C-flex (hydrophilic group C) or Akreos Adapt IOL (hydrophilic group A) was randomized for implantation in the fellow eye or vice versa of each patient. The Evaluation of Posterior Capsule Opacification (EPCO) area, EPCO score, and neodymium:YAG (Nd:YAG) capsulotomy rates were compared using digital photographs.

RESULTS

The study enrolled 68 patients. Although there was no significant difference at 1 month, the median EPCO score was statistically significantly lower in the hydrophobic group than in hydrophilic group C (P = .00) and hydrophilic group A (P = .000) at 3 years. There were no significant differences in the median EPCO area at 1 month; however, the area was statistically significantly less in the hydrophobic group than in hydrophilic group C and hydrophilic group A at 3 years (both P = .000). Four (12.9%) of 31 eyes in hydrophilic group C and 5 (16%) of 31 eyes in hydrophilic group A required an Nd:YAG capsulotomy; no eye in the hydrophobic group required a capsulotomy (P = .04 and P = .02, respectively).

CONCLUSION

Posterior capsule opacification was significantly less with the Acrysof hydrophobic acrylic IOL at 3 years.

FINANCIAL DISCLOSURE

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

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.

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.

Posterior capsule opacification in eyes with steroid-induced cataracts: Comparison of early results

PURPOSE

To evaluate posterior capsule opacification (PCO) development after cataract surgery in eyes with or without a history of steroid use.

SETTING

Iladevi Cataract & IOL Research Centre, Ahmedabad, India.

DESIGN

Comparative case series.

METHODS

This study comprised consecutive patients with a history of steroid intake (oral, inhaled, injectable, or topical) for at least 4 months who developed posterior subcapsular cataract (PSC) (study group) and patients without a history of steroid intake with uncomplicated PSC (control group). Standardized surgery was performed in both groups. Digital retroillumination photographic documentation was performed 1 month and 1 year postoperatively. The digital images were analyzed for PCO using Evaluation of Posterior Capsule Opacification (EPCO) software; the entire intraocular lens (IOL) optic and the central 3.0 mm optic area were evaluated. The EPCO score and EPCO area were determined.

RESULTS

One year postoperatively, the mean EPCO score was statistically significantly higher in the study group (n = 30) than in the control group (n = 60) (0.33 ± 0.37 [SD] versus 0.15 ± 0.26), as was the mean EPCO area (0.323 ± 0.36 versus 0.15 ± 0.26) (both P<.04). Within the central 3.0 mm optic area, the mean EPCO scores (0.149 ± 0.309 versus 0.003 ± 0.016 P<.04) and mean EPCO area values (0.149 ± 0.309 versus 0.003 ± 0.016) were statistically significantly higher in the study group (P<.04).

CONCLUSION

Steroid-induced PSC was associated with a higher risk for PCO after cataract surgery at the 1-year follow-up.

FINANCIAL DISCLOSURE

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

Interventions for preventing posterior capsule opacification

BACKGROUND

Posterior capsule opacification (PCO) remains the most common long-term complication after cataract surgery. It can be treated by Nd:YAG laser capsulotomy, however this may lead to other complications and laser treatment is not available in large parts of the developing world. Therefore, many studies try to find factors influencing the development of PCO.

OBJECTIVES

To summarise the effects of different interventions to inhibit PCO. These include modifications of surgical technique and intraocular lens (IOL) design, implantation of additional devices and pharmacological interventions.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, EMBASE, LILACS in March 2009 and reference lists of identified trial reports.

SELECTION CRITERIA

We included only prospective, randomised and controlled trials with a follow-up time of at least 12 months. Interventions included modifications in surgical technique explicitly to inhibit PCO, modifications in IOL design (material and geometry), implantation of additional devices and pharmacological therapy compared to each other, placebo or standard treatment.

DATA COLLECTION AND ANALYSIS

We extracted data and entered it into RevMan. We compared visual acuity data, PCO scores and YAG capsulotomy rates and performed a meta-analysis when possible.

MAIN RESULTS

Sixty six studies were included in the review. The review was divided into three parts. 1. Influence of IOL optic material on the development of PCO. There was no significant difference in PCO development between the different IOL materials (PMMA, hydrogel, hydrophobic acrylic, silicone) although hydrogel IOLs tend to have higher PCO scores and silicone IOLs lower PCO scores than the other materials. 2. Influence of IOL optic design on the development of PCO. There was a significantly lower PCO score (-8.65 (-10.72 to -6.59), scale 0 to 100) and YAG rate (0.19 (0.11 to 0.35)) in sharp edged than in round edged IOLs, however not between 1-piece and 3-piece IOLs. 3. Influence of surgical technique and drugs on the development of PCO. There was no significant difference between different types of intraoperative/postoperative anti-inflammatory treatment except for treatment with an immunotoxin (MDX-A) which led to a significantly lower PCO rate.

AUTHORS' CONCLUSIONS

Due to the highly significant difference between round and sharp edged IOL optics, IOLs with sharp (posterior) optic edges should be preferred. There is no clear difference between optic materials. The choice of postoperative anti-inflammatory treatment does not seem to influence PCO development.

Comparison of posterior capsule opacification development with 3 intraocular lens types: five-year prospective study

PURPOSE

To compare the effects of hydrophobic acrylic, silicone, and heparin-surface-modified poly(methyl methacrylate) (HSM PMMA) intraocular lenses (IOLs) on posterior capsule opacification (PCO).

METHODS

In this 5-year prospective study, the same surgeon performed standard phacoemulsification in patients who were randomized to implantation of a round-edged HSM PMMA IOL (809C), a round-edged silicone IOL (SI-40NB), or a sharp-edged hydrophobic acrylic IOL (AcrySof MA60BM). The neodymium:YAG capsulotomy rate was recorded. To evaluate PCO and the position of the anterior capsulorhexis, retroillumination digital photographs were taken 5 years postoperatively and analyzed using the POCOman computer-analysis system.

RESULTS

After 5 years, there was no significant difference in the fraction or severity of PCO between the silicone IOLs and acrylic IOLs (both P =1.0). The silicone IOL group had a significantly higher capsulotomy rate (29%) than the acrylic IOL group (8%) (P=.0068). The HSM PMMA IOL group had a significantly higher PCO fraction, severity, and capsulotomy rate (54%) than the silicone and acrylic groups. In all eyes, the fraction (P=.0076) and severity (P=.0081) of PCO were statistically significantly higher when the anterior capsulorhexis was partly decentered than when it was completely on the optic; within each IOL group, there was no significant difference.

CONCLUSION

After 5 years, there was no significant difference in the semiquantitative evaluation of PCO between the sharp-edged acrylic IOL and round-edged silicone IOL. Eyes with the HSM PMMA IOL had more PCO than eyes with the other IOLs.

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.

Interventions for preventing posterior capsule opacification

BACKGROUND

Posterior capsule opacification (PCO) remains the most common long-term complication after cataract surgery. It can be treated by Nd:YAG laser capsulotomy, however, this may lead to other complications and laser treatment is not available in large parts of the developing world. Therefore, many studies try to find factors influencing the development of PCO.

OBJECTIVES

To summarise the effects of different interventions to inhibit PCO. These include modifications of surgical technique and intraocular lens (IOL) design, implantation of additional devices and pharmacological interventions.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, EMBASE, LILACS in January 2007 and reference lists of identified trial reports.

SELECTION CRITERIA

We included only prospective, randomised and controlled trials with a follow-up time of at least 12 months. Interventions included modifications in surgical technique explicitly to inhibit PCO, modifications in IOL design (material and geometry), implantation of additional devices, and pharmacological therapy, compared to each other, placebo or standard treatment.

DATA COLLECTION AND ANALYSIS

Data were extracted and entered into Review Manager. Visual acuity data, PCO score and YAG capsulotomy rates were compared and a meta-analysis was performed when possible.

MAIN RESULTS

Fifty three studies were included in the review. The review was divided into three parts. (1) Influence of IOL optic material on the development of PCO. Compared to other materials, the meta-analysis of the included studies showed a significantly higher PCO score (overall effect: 12.39 (95% confidence interval: 9.82 to 14.95), scale 0 to 100) and YAG rate (odds ratio: 8.37 (3.74 to 20.36)) only in hydrogel IOLs. (2) Influence of IOL optic design on the development of PCO. There was a significantly lower PCO score (-8.65 (-10.72 to -6.59), scale 0 to 100) and YAG rate (0.19 (0.11 to 0.35)) in sharp edged than in round edged IOLs, however, not between 1-piece and 3-piece IOLs. (3) Influence of surgical technique and drugs on the development of PCO. There was no significant difference between different types of intra-/postoperative anti-inflammatory treatment except for treatment with an immunotoxin (MDX-A) leading to a significantly lower PCO rate.

AUTHORS' CONCLUSIONS

Due to the highly significant difference between round and sharp edge IOL optics, IOLs with sharp (posterior) optic edges should be preferred. There is no clear difference between optic materials, except for hydrogel IOLs, that showed more PCO than the other materials. The choice of postoperative anti-inflammatory treatment does not seem to influence PCO development.

Anterior capsule cover and axial movement of intraocular lens

PURPOSE

To measure optic shift (OS) of a single piece monofocal intraocular lens (IOL) with varying relationships between anterior capsule cover and IOL optic.

METHODS

This is a prospective randomized masked study of 150 eyes undergoing phacoemulsification. Eyes received either option: 360 degrees total capsule cover (group I); partial cover (group II); or no cover (group III). OS was calculated as difference in anterior chamber depth after administration of cyclopentolate 1% and pilocarpine 2% on IOLMaster at separate visits at 6 months follow-up. Subsequently, using retro-illumination photographs, percentage area of capsule cover was calculated. OS within and between groups I and II was analyzed. The impact of one quartile change in area of capsule cover on percentage change in OS was measured for both groups. Unpaired t-test, correlation, and regression were applied.

RESULTS

In groups I, II, and III, mean age of patients was 56.68+/-6.38, 57.09+/-7.34, 59.15+/-6.35 years, respectively; mean OS (mm) was 1.25+/-0.28, 1.20+/-0.24; 0.95+/-0.26 (P=0.013), respectively; and percentage area of capsule cover (%) was 47.35+/-10.48, 33.83+/-10.11, 0.16+/-0.13 (P=0.001), respectively. Mean percentage area of capsule cover in group I vsgroup II was significant (P=0.001). OS was 1.22+/-0.26 mm in groups I and II (combined) vs0.95+/-0.26 mm in group III (P=0.004, (0.06, 0.33)). OS in group I vsgroup II was not significant (P=0.46). Correlation coefficient was r=0.38 (P<0.001). With every increment on quartile (a quartile is any of the three values which divide the sorted data set into four equal parts, so that each part represents one-fourth of the sample or population) class of area of capsule cover the OS increased by 0.12 mm.

CONCLUSION

The OS differed significantly between total and partial cover groups combined vsno cover group.

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.

Effect of cortical cleaving hydrodissection on posterior capsule opacification in age-related nuclear cataract

PURPOSE

To evaluate the effect of multiquadrant cortical cleaving hydrodissection on the development of posterior capsule opacification (PCO) after phacoemulsification.

SETTING

Iladevi Cataract and IOL Research Center, Ahmedabad, India.

METHODS

A prospective randomized triple blind clinical trial was conducted in 86 eyes (86 patients) having phacoemulsification. Eyes were assigned randomly to Group 1, multiquadrant cortical cleaving hydrodissection and hydrodelineation (n = 48 eyes), or Group 2, no multiquadrant cortical cleaving hydrodissection, only hydrodelineation (n = 38 eyes). Age-related nuclear sclerosis (grading system of 1 to 5) and age greater than 50 years were included. Diabetes mellitus and associated eye diseases were excluded. Standard phacoemulsification with implantation of an AcrySof MA30BA intraocular lens (IOL) was done in both groups. High-resolution digital retroillumination images of the posterior capsule were analyzed at 4 years using POCOman software. Seven patients dropped out (8.1%). Outcome measures were incidence and percentage area of PCO. Test of proportions, independent sample t test, and 95% confidence intervals (CIs) were noted.

RESULTS

In Groups 1 and 2, the mean age was 58 years +/- 4 (SD) and 57 +/- 5 years, respectively (P = .702; 95% CI, 1.90-2.81); mean follow-up was 48.4 +/- 2.5 months and 49.3 +/- 1.9 months, respectively (P = .687; 95% CI, 1.186-0.7856); incidence of PCO was 11 of 44 (25%) and 12 of 35 (34.3%), respectively (P = .317; 95% CI, 0.359-0.0889); percentage area of PCO was 14.3% and 25.6%, respectively (P = .006; 95% CI, -19.19 to -3.44). One of 44 eyes (2.27%) and 2 of 35 eyes (5.7%) in the groups, respectively, had a neodymium:YAG capsulotomy.

CONCLUSION

Although no difference was noted in the incidence of PCO, in eyes that had PCO, the percentage of the area of the central posterior capsule involved by PCO was significantly lower in eyes that had multiquadrant cortical cleaving hydrodissection than in those that did not.

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.

Effect of hydrodissection alone and hydrodissection combined with rotation on lens epithelial cells

PURPOSE

To evaluate the impact of corticocleaving hydrodissection alone and hydrodissection combined with rotation on lens epithelial cells (LECs) and residual cortical fibers (RCFs).

SETTING

Iladevi Cataract and IOL Research Center, Ahmedabad, India.

METHODS

An experimental laboratory study of 20 fresh human cadaver eyes (10 pairs) was conducted. A single eye from each pair was assigned to the control group, in which no hydrodissection and no rotation were performed (control). The other eye was randomized to corticocleaving hydrodissection alone (Group 1) or corticocleaving hydrodissection with rotation (Group 2). Cataract extraction was standardized. Capsule polishing was omitted. Area of LEC loss (%) in the preequatorial zone (PZ) and equatorial zone (EZ) was calculated as: [Area of capsule without cells/Total area of capsule] x 100. Area of presence of RCFs (%) was calculated as: [Circumference of EZ of capsule with RCF/Total circumference of EZ of the capsule] x 100. The Mann-Whitney U and the Wilcoxon signed rank tests were applied.

RESULTS

In the control group, area of cell loss (%) was 3.9 +/- 3.2 in the PZ and 2.7 +/- 0.8 in the EZ; presence of RCFs (%) was 83.8 +/- 1.7. Area of LEC loss (%) in Groups 1 and 2 was 24.8 +/- 4.5 and 42.6 +/- 5.4 (P = .008) in the PZ and 22.4 +/- 2.1 and 54 +/- 2.5 (P = .008) in the EZ, respectively. Area of presence of RCFs (%) in Groups 1 and 2 was 34.2 +/- 3.7 and 23.7 +/- 3.7 (P = .008), respectively.

CONCLUSION

Corticocleaving hydrodissection combined with rotation removed significant quantities of LECs and RCFs.

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.