Quantification of posterior capsule opacification with round and sharp edge intraocular lenses

doi:10.1016/S0161-6420(02)01980-2

Ophthalmology

Volume 110, Issue 4, April 2003, Pages 772-780

Presented in part at the annual meeting of the American Academy of Ophthalmology, New Orleans, Louisiana, November 2001.

https://doi.org/10.1016/S0161-6420(02)01980-2 Get rights and content

Abstract

Purpose

To quantitatively evaluate and compare intraocular lenses (IOLs) with a round or sharp optic edge design for posterior capsule opacification (PCO).

Study design

Prospective comparative observational case series.

Participants/materials

Photographs from 174 eyes were analyzed for PCO at the Department of Ophthalmology, Ruprecht-Karls-University of Heidelberg, Heidelberg, Germany.

Main outcome measures

Part I: 121 eyes of 121 patients were analyzed for quantification of PCO. IOLs evaluated were Corneal ACR6 (n = 21), Alcon Acrysof (n = 20), Allergan AR40 (n = 27), Pharmacia 811 one-piece polymethyl methacrylate (PMMA) IOL (n = 24), and Pharmacia 911A silicone IOL (n = 29). Mean follow-up was 14.01 ± 2.81 months; mean patient age was 73.2 ± 7.3 years. The morphologic PCO formation was evaluated for the entire optic and in the central 3-mm zone. Part II: In 53 eyes of 46 patients aged 73.4 ± 10.8 years with an Alcon Acrysof IOL, PCO formation and capsulorrhexis/optic overlapping were analyzed 34.2 ± 4 months after cataract surgery using EPCO Software.

Results

Part I: The PCO values of the entire optic were for Corneal ACR6, 1.93 ± 0.62; PMMA, 0.64 ± 0.63; AR40, 0.55 ± 0.28; Alcon Acrysof, 0.145 ± 0.27; and 0.161 ± 0.181 for the Pharmacia 911A IOL (P < 0.01). The PCO values of the central 3-mm zone were for Corneal ACR6, 1.64 ± 0.96; PMMA, 0.49 ± 0.39; AR40, 0.22 ± 0.32; Alcon Acrysof, 0.08 ± 0.21; and 0.06 ± 0.11 for the Pharmacia 911A IOL (P < 0.01). Part II: Average overlapping of capsulorrhexis and Acrysof IOL optic was 40.5% ± 12.4%. There was a significant correlation between PCO values and overlapping (r = −0.69, P < 0.001).

Conclusions

The sharp-edge IOL types (Alcon Acrysof and Pharmacia 911A silicone IOL) resulted in statistically significantly lower PCO values for analysis of the entire optic area and central 3-mm zone. There was no statistically significant difference in PCO values between the two sharp-edge optic IOLs. An overlapping of capsulorrhexis rim and the anterior IOL optic surface of more than 20% resulted in significantly lower PCO values with the Acrysof IOL.

Section snippets

Image analysis system

The computerized system by Tetz and Nimsgern7 (EPCO) is an established system that has been used for PCO research in several studies.14, 15, 22, 23, 24, 25 With this system, standardized retroillumination slit-lamp photographs are digitized and imported into the program. A detailed description of the retroillumination photographs and camera settings is given in a previous publication by Tetz et al.14

In the EPCO program the desired area of evaluation (e.g., the IOL optic area) is first marked,

Patients

At present, our PCO database consists of approximately 1000 patients. Standardized retroillumination photographs have been analyzed for all patients using the EPCO software. Posterior capsule opacification values were stored in a database together with clinical information. The data analyzed in this study were taken from this database.

Statistical analysis

Statistical evaluation included the use of frequency distribution diagrams, the analysis of variance test, and nonparametric statistical tests, such as the Kruskal-Wallis test and the Spearman correlation using the programs MS Ecxel 2000, SYSTAT 5.03 for Windows, and STATISTICA 4.5 for Windows.

Part I

The PCO values of the entire optic were for the Corneal ACR6, 1.93 ± 0.62; PMMA, 0.64 ± 0.63; AR40, 0.55 ± 0.28; Alcon Acrysof, 0.145 ± 0.27; and 0.161 ± 0.181 for the Pharmacia 911A IOL (P < 0.01, Kruskal-Wallis test; Fig 4).

The PCO values of the central 3-mm optic zone were for the Corneal ACR6, 1.64 ± 0.96; PMMA, 0.49 ± 0.39; AR40, 0.22 ± 0.32; Alcon Acrysof, 0.08 ± 0.21; and 0.06 ± 0.11 for the Pharmacia 911A IOL (P < 0.01, Kruskal-Wallis test; Fig 5).

The two IOL types with sharp-edge

Discussion

Fifty years ago, it had already been shown that the implantation of an IOL into the capsular bag after extracapsular cataract surgery reduced the incidence and amount of PCO compared with aphakic eyes or eyes with sulcus fixation of an IOL.1, 2, 3, 4, 7, 8, 9, 10, 16, 26, 27 The pressure of the optic against the posterior capsule creates a barrier effect that reduces PCO. However, PCO rates still remained around 30% to 50% in the 1980s and early 1990s.5

A biconvex IOL optic has been shown to

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These limitations have prompted researchers to develop technologies to reduce the incidence of PCO. Among these developments are the use of various surgical techniques, square-edge IOLs composed of hydrophobic material [8,12,13] and surface modifications to IOLs using bioactive substances [14–17]. These factors can improve the biocompatibility of IOLs which come into direct contact with the ocular tissues, cells, and proteins.
Cataracts result from opacification of the ocular lens and represent the leading cause of blindness worldwide. After surgical removal of the diseased lens material and implantation of an artificial intraocular lens, up to 50% of cataract patients develop a secondary lens defect called posterior capsular opacification (PCO). While vision can be restored in PCO patients by a laser-mediated capsulotomy, novel therapies involving inhibition of aldose reductase are now being developed to prevent PCO development and complications of laser capsulotomy. A question we wished to address was whether cataract surgeons believe there is an unmet need for a preventative PCO therapy, whether they would prescribe such a therapy were it available, and to assess their perceptions regarding the benefits of and obstacles to adopting novel PCO therapies in the place of laser capsulotomy. We gathered perspectives from adult, pediatric, and veterinary cataract surgeons using an online questionnaire. From 161 surgeon responses, we found that the majority of adult, pediatric, and veterinary cataract surgeons (78% n = 35, 88% n = 37, and 96% n = 71 respectively) believed there is an unmet need for preventative PCO therapy, with more than 95% expressing interest in incorporating such therapy into surgical protocols. Perceived benefits included optimizing visual outcomes, avoiding the need for additional procedures, eliminating complications related to neodymium:yttrium-aluminum-garnet laser, preserving the posterior capsule particularly in patients receiving multifocal intraocular lens implants, providing a viable solution for PCO in animals, and using it in developing countries that lack access to neodymium:yttrium-aluminum-garnet lasers. Perceived obstacles included potential lack of reimbursement by insurance companies, and the need for strong efficacy and safety profiles. Among adult surgeons, 70% (n = 31) indicated that preventative PCO therapy could add value to premium intraocular lens packages. Our studies revealed that cataract surgeons overwhelmingly support the development of preventative PCO therapy, and that clinical trials will play a critical role to test the safety and efficacy of specific therapeutic agents.
Edge profile of commercially available square-edged intraocular lenses: Part 2
2019, Journal of Cataract and Refractive Surgery
To analyze the sharpness of the posterior optic edge and edge thickness of intraocular lenses (IOLs) marketed with a square-edged profile.
University of Brighton and Brighton and Sussex University Hospitals NHS Trust, Brighton, England.
Laboratory study.
Fourteen square-edged 20.0 diopter IOLs were analyzed, including 9 hydrophobic IOLs (AF-1, AF-1 iSert, Clareon, EyeCee One Crystal, CT Lucia, Envista, EyeCee One, Vivinex iSert, and RayOne Hydrophobic) and 5 hydrophilic IOLs (Asphira, CT Asphina, Incise, Synthesis, and RayOne Hydrophilic). All the IOLs were scanned following a previously published standardized technique using environmental scanning electron microscopy. The posterior optic edges were scanned at a magnification of ×500 and ×200 to measure the radius of curvature of the posterior optic edges and the optic edge thickness.
The radius of curvature of the posterior optic edges ranged from 4.6 to 20.6 μm. Except for the Incise IOL (7.7 μm), all hydrophilic IOLs (Synthesis [10.6 μm], Asphira [13.7 μm], RayOne Hydrophilic [14.0 μm], CT Asphina [13.7 μm]) had a radius of curvature greater than 10.0 μm. For the hydrophobic IOLs, the radius of curvature was less than 10.0 μm for the Clareon (7.9 μm), EyeCee One Crystal (4.7 μm), Vivinex iSert (7.6 μm), and CT Lucia (4.6 μm), and greater than 10.0 μm for the Envista (19.7 μm), EyeCee One (13.7 μm), AF-1 iSert (19.7 μm), AF-1 (19.7 μm) and the RayOne Hydrophobic (20.6 μm). The Vivinex iSert (150.5 μm) and the Incise (218.2 μm) were the thinnest IOLs, and the RayOne Hydrophobic (375.8 μm) and RayOne Hydrophilic IOLs (477.1 μm) were the thickest of the hydrophobic and hydrophilic IOLs, respectively.
Commercially marketed square-edged IOLs still differed in the sharpness of the posterior optic edge. More hydrophobic IOLs have rounder edges than those studied 10 years ago. Variations in the edge profile of hydrophobic IOLs were greater compared with the hydrophilic IOLs.
Long-term Posterior Capsule Opacification Reduction with Square-Edge Polymethylmethacrylate Intraocular Lens: Randomized Controlled Study
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To objectively assess the long-term posterior capsule opacification (PCO) and neodymium-doped yttrium aluminium garnet (Nd:YAG) capsulotomy rate of a square-edge (SE) polymethylmethacrylate (PMMA) intraocular lens (IOL) modification in comparison with a round-edge (RE) PMMA IOL or an SE hydrophobic acrylic IOL (SE-Acrylic).
Prospective, randomized, controlled fellow eye clinical study.
Ninety-four patients scheduled for bilateral phacoemulsification had an SE-PMMA IOL implanted in 1 eye. An RE-PMMA IOL was implanted in the fellow eye in 46 patients (group A), and an SE-Acrylic IOL was implanted in the fellow eye in 48 patients (group B). Randomization was used to determine group assignment and which IOL was implanted in the first eye to undergo surgery.
Evaluation of Posterior Capsule Opacification (EPCO) image analysis software was used to objectively grade PCO density from standardized, high-resolution retroillumination photographs obtained annually for the first 5 postoperative years and at year 9.
The PCO scores and Nd:YAG capsulotomy rate.
Nine-year follow-up was achieved by 72% from group A and 63% from group B. In group A, the mean PCO score was significantly lower in the SE-PMMA IOL eyes compared with the contralateral RE-PMMA eyes at all follow-up visits (P < 0.05). In group B, the mean PCO score was statistically lower in the SE-PMMA IOL eyes compared with the contralateral SE-Acrylic IOL eyes at all but the 1- and 3-year follow-up visits. Nine-year Nd:YAG capsulotomy rates were 2% for SE-PMMA IOLs versus 37% for RE-PMMA IOLs in group A (P < 0.001), and 4% for SE-PMMA IOLs versus 10% for SE-Acrylic IOLs in group B (P = 0.435). The RE-PMMA PCO rate did not plateau and continued to increase throughout the 9-year study period.
This prospective, 9-year fellow eye comparison study suggests that an inexpensive PMMA IOL design modification—a squared optic edge—could significantly reduce the burden of vision-impairing secondary membrane in developing countries.
Intraindividual comparison of capsule behavior of 2 hydrophobic acrylic intraocular lenses during a 5-year follow-up
2017, Journal of Cataract and Refractive Surgery
Citation Excerpt :
In vitro studies13 have shown that the migration of human lens epithelial cells (LECs) under a hydrophobic acrylic IOL is substantially blocked compared with PMMA and silicone IOLs. However, our PCO scores are slightly higher than those reported by other studies1,5,10–12,14,15 for other or even the same hydrophobic acrylic IOLs (Table 1). The different follow-up periods and evaluation methods of these previous studies might account for this.
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.
Hospital St. John, Vienna, Austria.
Randomized controlled prospective case series.
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.
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.
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.
Intraindividual comparative analysis of capsule opacification after implantation of 2 single-piece hydrophobic acrylic intraocular lenses models: Three-year follow-up
2015, Journal of Cataract and Refractive Surgery
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.
Hospital of St. John of God, Vienna, Austria.
Comparative randomized controlled double-blind clinical trial.
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.
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.
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.
No author has a financial or proprietary interest in any material or method mentioned.
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Quantification of posterior capsule opacification with round and sharp edge intraocular lenses☆

Abstract

Purpose

Study design

Participants/materials

Main outcome measures

Results

Conclusions

Section snippets

Image analysis system

Patients

Statistical analysis

Part I

Discussion

Surv Ophthalmol

J Cataract Refract Surg

Ophthalmology

J Cataract Refract Surg

J Cataract Refract Surg

Am J Ophthalmol

J Cataract Refract Surg

J Cataract Refract Surg

J Cataract Refract Surg

YAG-Laser-Kapsulotomie bei Retinitis pigmentosa. Ophthalmologe

J Cataract Refract Surg

Cataract Refract Surg

Ophthalmo-Chirurgie

Curr Opin Ophthalmol

Curr Eye Res

Hum Gene Ther

Zur Entwicklungsgeschichte der Intraokularlinsen

Ophthalmologe