Peripheral Posterior Capsule Opacification Research Articles

Uveal and capsular biocompatibility of a new hydrophobic acrylic microincision intraocular lens

To evaluate uveal biocompatibility and capsular bag opacification of a new hydrophobic acrylic microincision intraocular lens (IOL) in comparison with a commercially available 1-piece hydrophobic acrylic IOL. John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Experimental study. Eight New Zealand rabbits underwent bilateral phacoemulsification and implantation of the preloaded Nanex multiSert IOL in one eye and a commercially available preloaded lens (AcrySof IQ in UltraSert, model AU00T0) in the contralateral eye. A slitlamp examination was performed weekly for 4 weeks. The rabbits were then killed humanely and their globes enucleated. Capsular bag opacification was assessed from the Miyake-Apple view, and the eyes were subjected to histopathologic evaluation. Postoperative inflammatory reactions were similar between the test and control eyes in the 8 New Zealand rabbits. The mean postmortem central posterior capsule opacification (PCO) was 0.93 ± 0.73 in the test group and 1.19 ± 0.53 in the control group. The mean postmortem peripheral PCO was 1.75 ± 0.92 in the test group and 2.06 ± 0.77 in the control group. Central and peripheral PCO scores were not statistically different between the test and control groups (P = .41 and P = .35, respectively, 2-tailed t test: paired 2-sample for means). A new 1-piece hydrophobic acrylic microincision IOL incorporating an ultraviolet-ozone treatment on the posterior surface performed similarly to a commercially available 1-piece hydrophobic acrylic IOL in terms of uveal and capsular biocompatibility in the rabbit model. To our knowledge, this is the first hydrophobic acrylic microincision IOL to demonstrate similar PCO performance when compared with a conventional, commercially available IOL.

Posterior capsule opacification prevention by an intraocular lens incorporating a micropatterned membrane on the posterior surface.

To evaluate posterior capsule opacification (PCO) with a new hydrophobic acrylic intraocular lens (IOL) featuring a new micropatterned membrane, in comparison with a commercially available 1-piece hydrophobic acrylic IOL. John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Experimental study. Twelve New Zealand rabbits had bilateral phacoemulsification and implantation of a ClearSight unpatterned IOL (Group 1), a ClearSight Sharklet-patterned IOL (Group 2), or a control, commercially available IOL (Group 3) (8 IOLs in each group). Slit-lamp examination was performed weekly for 4 weeks. The rabbits were then killed humanely, and their globes enucleated. Capsular bag opacification was assessed from the Miyake-Apple view, and the eyes underwent histopathology. The mean postmortem central PCO was 1.87 ± 1.35 in Group 1, 1.06 ± 1.23 in Group 2, and 3.14 ± 0.89 in Group 3. Peripheral PCO was 2.18 ± 1.36 in Group 1, 1.5 ± 1.03 in Group 2, and 3.57 ± 0.53 in Group 3. When comparing central and peripheral PCO between Groups 1 and 3, the difference was not statistically significant, but it was statistically significant between Groups 2 and 3 (P = .003 and P = .0003, t test with Bonferroni correction). Unique discontinuous features comprising the micropattern allow for focal adhesions to be precisely guided and therefore controlling cell migration. The patterned membrane incorporated on the posterior surface of the IOL significantly reduced capsular bag opacification compared with a commercially available control IOL.

Depletion of Myo/Nog Cells in the Lens Mitigates Posterior Capsule Opacification in Rabbits.

Posterior capsule opacification (PCO) is a vision-impairing disease that occurs in some adults and most children after cataract surgery. Contractile myofibroblasts contribute to PCO by producing wrinkles in the lens capsule that scatter light. Myofibroblasts in the lens originate from Myo/Nog cells named for their expression of the MyoD transcription factor and bone morphogenetic protein inhibitor noggin. In this study we tested the effects of depleting Myo/Nog cells on development of PCO. Myo/Nog cells were eliminated by injecting the G8 antibody conjugated to 3DNA nanocarriers for the cytotoxin doxorubicin (G8:3DNA:Dox) during cataract surgery in rabbits. The severity of PCO was scored by slit lamp analysis, gross and histologic observation, and immunofluorescence localization of α-smooth muscle actin. G8:3DNA:Dox specifically induced cell death in Myo/Nog cells in the lens. None of the lenses administered G8:3DNA containing 9 to 36 μM doxorubicin developed greater than trace levels of central PCO and few myofibroblasts were present on the capsule. Less than 9% of these lenses exhibited greater than mild levels of peripheral PCO. Doxorubucin itself reduced PCO; however, myofibroblasts and wrinkles were abundant in the lens, and off-target effects were observed in the ciliary processes and cornea. Myo/Nog cells are the primary source of myofibroblasts in the lens after cataract surgery. Targeted depletion of Myo/Nog cells has potential for preventing PCO and preserving vision.

Evaluation of stability and capsular bag opacification with a foldable intraocular lens coupled with a protective membrane in the rabbit model

To evaluate the stability and capsular bag opacification of a smooth or a patterned silicone protective membrane implanted in the bag with secondary placement of an intraocular lens (IOL). John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Experimental study. Twelve New Zealand rabbits had bilateral implantation of a protective membrane and an IOL or an IOL alone. Three groups of 8 eyes each received the IOL and the smooth protective membrane, the IOL and the patterned membrane, or the IOL alone. Slitlamp examination was performed weekly for 4 weeks. The rabbits were then humanely killed and their globes enucleated. Capsular bag opacification was scored based on the Miyake-Apple view, and the eyes underwent histopathology. At 4 weeks, the mean central posterior capsule opacification (PCO) score was 0.28 ± 0.32 (SD) in all eyes with a protective membrane and 2.08 ± 1.28 in eyes with the IOL alone (P < .00001, Student t test). Peripheral PCO and Soemmerring ring formation were also significantly less in eyes with the protective membrane. Histopathologically, the posterior capsules were relatively clear in most IOLs with the protective membrane. The smooth and patterned protective membranes showed a significant difference in overall capsular bag opacification formation compared with the IOLs without the membrane. The circular geometry of the protective membrane led to expansion of the capsular bag and appeared to prevent capsular bag opacification. Further studies are warranted to assess whether the pattern on the device's posterior surface further enhances this effect. No author has a financial or proprietary interest in any material or method mentioned.

Evaluation of uveal and capsule biocompatibility of a single-piece hydrophobic acrylic intraocular lens with ultraviolet–ozone treatment on the posterior surface

To evaluate a single-piece hydrophobic acrylic intraocular lens (IOL) with ultraviolet-ozone (UV-O3) treatment on the posterior surface and compare it with an identical untreated IOL in a rabbit model. John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Experimental study. Study IOLs were implanted in the right eyes and control IOLs in the left eyes of 10 New Zealand rabbits. Slitlamp examinations were performed 1 to 6 weeks postoperatively. Neodymium:YAG (Nd:YAG) posterior capsulotomy was performed in both eyes of 5 rabbits after the 4-week slitlamp examination. At 6 weeks, the rabbits were killed humanely and their globes were enucleated. Capsular bag opacification was scored from the posterior aspect (Miyake-Apple view), and the eyes were processed for histopathology. At 4 weeks, the mean posterior capsule opacification (PCO) scores were 0.88 ± 0.33 (SD) in the study eyes and 2.55 ± 1.13 in the control eyes (P=.003, 2-tailed paired t test). Performance of Nd:YAG posterior capsulotomy was similar in both groups. Gross postmortem examination also showed statistically less peripheral PCO in eyes with the study IOLs than in control eyes. There was no difference in histopathologic findings between study eyes and control eyes and no signs of untoward inflammation or toxicity in any eye evaluated. Treatment of the posterior surface of a single-piece hydrophobic acrylic IOL with UV-O3 appears to prevent PCO, likely by increasing adhesion between the posterior capsule and the IOL while retaining uveal biocompatibility. Performance of Nd:YAG posterior capsulotomy was similar between treated IOLs and untreated IOLs.

Capsular bag opacification with a new accommodating intraocular lens

To evaluate the biocompatibility and capsular bag opacification of an accommodating intraocular lens (IOL) containing large haptic elements that separate the anterior and posterior capsules. John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Experimental study. Bilateral phacoemulsification with IOL implantation was performed in 6 New Zealand rabbits. Each animal received a study (accommodating) IOL and a control (1-piece hydrophobic acrylic) IOL. Eyes were examined at the slitlamp from 1 day through 6 weeks postoperatively. The globes were then enucleated and evaluated grossly. Capsular bag opacification was scored from the posterior aspect (Miyake-Apple view). The eyes were then processed for complete histopathologic evaluation. At 6 weeks, the mean posterior capsule opacification (PCO) clinical score was 0.5 ± 0.3 (SD) in the study group and 3.0 ± 0.9 in the control group (P=.001, 2-tail paired t test). Anterior capsule opacification was practically absent in the study group and mild in the control group. Miyake-Apple posterior view showed a mean central PCO score of 0 ± 0 in the study group and 3.0 ± 1.1 in the control group (P=.001), peripheral PCO score of 0.7 ± 0.4 and 3.5 ± 0.8 (P=.0006), respectively, and Soemmerring ring score of 2.3 ± 0.8 and 7.0 ± 2.8 (P=.01), respectively. Histopathology showed no signs of toxicity in any eye. The study IOL maintained an expanded capsular bag secondary to the large size of the haptic elements, which appears to prevent capsular bag opacification.

Evaluation of a new single-piece 4% water content hydrophobic acrylic intraocular lens in the rabbit model

To evaluate uveal and capsular biocompatibility of a 1-piece intraocular lens (IOL) manufactured from a new hydrophobic acrylic material that incorporates a barrier step at the optic-haptic junctions. John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Experimental study. The study IOL (Eternity-Uni W-60) was implanted in the right eyes of 5 New Zealand rabbits and the control IOL (Acrysof SN60WF) in the left eyes. Slitlamp examination was performed 1 through 4 weeks postoperatively. After death, the globes were enucleated and fixed in formalin. Capsular bag opacification scoring (Miyake-Apple view) was then performed followed by complete histopathology. At the 4-week examination, the mean posterior capsule opacification (PCO) score was 1.5 ± 1.0 (SD) in the study group and 2.2 ± 1.09 in the control group (P=.02). Anterior capsule opacification (ACO) was not present in the study eyes and was mild in the control eyes. On gross examination, the mean central PCO score was 0.9 ± 0.65 in the study group and 1.7 ± 1.20 in the control group (P=.07); the mean peripheral PCO score was 1.3 ± 0.67 and 2.4 ± 1.14 (P=.01) and the mean Soemmerring ring score was 3.8 ± 0.44 and 4.2 ± 1.09, respectively (P=.47). Histopathology confirmed that both IOLs were equally tolerated by the rabbit eyes. In this rabbit study, the new hydrophobic acrylic material was biocompatible. The barrier step incorporated to the optic-haptic junctions has the potential to enhance PCO prevention.

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

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

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

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. John A. Moran Eye Center, University of Utah, USA. Experimental study. 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. 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. 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. No author has a financial or proprietary interest in any material or method mentioned.

Findings of an experimental study in a rabbit model on posterior capsule opacification after implantation of hydrophobic acrylic and hydrophilic acrylic intraocular lenses

Study on cell growth on the posterior capsule after implantation of hydrophobic acrylic (Acrysof SA 60 AT) and hydrophilic acrylic (Akreos Disc) intraocular lenses (IOL) in a rabbit model and comparison of posterior capsule opacification (PCO). Phacoemulsification was performed in 22 rabbit eyes, and two different IOL types (Acrysof SA60 AT and Akreos Disc) were implanted. These IOLs had the same optic geometry (square edged) but different material and design. Central PCO (CPCO), peripheral PCO (PPCO), Sommering's ring (SR) formation, type of growth, extension of PCO, cell type, inhibition, and fibrosis were evaluated three weeks after surgery. Histological sections of each globe were prepared to document the evaluation of PCO. No statistically significant difference was observed between a hydrophobic acrylic IOL and a hydrophilic acrylic IOL in relation to the CPCO, PPCO, type of growth, extension, cell type, inhibition, and fibrosis. Statistically significant difference was observed in relation to the formation of SR with Acrysof SA 60 AT group presenting more SR than Akreos Disc group. PCO was not influenced by the material of the IOL or the design of the haptics of the IOLs we studied.

Long-term effect of optic edge design in an acrylic intraocular lens on posterior capsule opacification

To compare the posterior capsule opacification (PCO) inhibiting effect of the sharp posterior optic edge design of the Sensar OptiEdge AR40e intraocular lens (IOL) with that of the double-round edge design of the Sensar AR40 IOL over a period of 3 years. Department of Ophthalmology, Medical University of Vienna, Vienna, Austria. Fifty-three patients with bilateral age-related cataract (106 eyes) were included in this randomized prospective bilateral patient- and examiner-masked clinical trial with intraindividual comparison. Each study patient had cataract surgery in both eyes and received a Sensar AR40 IOL (anterior and posterior round optic edges) in 1 eye and a Sensar OptiEdge AR40e IOL (round anterior and sharp posterior optic edge) in the other eye. Follow-up examinations were at 1 week, 1 and 6 months, and 1, 2, and 3 years. Digital retroillumination images were taken of each eye. The amount of PCO was assessed subjectively at the slitlamp and objectively using automated image-analysis software (AQUA) 1, 2, and 3 years after surgery. The sharp-edged AR40e lens showed significantly less regeneratory and fibrotic PCO 1, 2, and 3 years after surgery. The mean AQUA PCO score was 2.18 for the AR40 and 1.00 for the AR40e lens after 1 year; 2.94 and 1.56 after 2 years, and estimated at 3.13 and 1.77, respectively, after 3 years (scale 0 to 10; P<.001). The neodymium:YAG laser capsulotomy rate was significantly higher in the AR40 group. The AR40e lens also led to less peripheral fibrotic PCO. There was no significant difference in complaints concerning edge glare between the groups. Compared with the AR40 IOL, the sharp posterior optic edge design of the Sensar OptiEdge AR40e IOL led to significantly less PCO 1, 2, and 3 years postoperatively. In contrast with most past studies on PCO-preventative factors, this study varied only 1 parameter, namely the optic edge design, and the main outcome measure (PCO) was assessed with an objective image-analysis system.

Posterior capsule opacification in rabbit eyes implanted with 1-piece and 3-piece hydrophobic acrylic intraocular lenses

To evaluate the outcome of posterior capsule opacification (PCO) after implantation in rabbit eyes of currently available 3-piece and 1-piece hydrophobic acrylic intraocular lenses (IOLs) with square optic edges. John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. The 3-piece designs evaluated were the AR40e (Advanced Medical Optics Inc.) and the MA60AC (Alcon, Inc.); the 1-piece designs were the SA60AT and the SA30AT (Alcon, Inc.). Nine lenses of each type were implanted in a randomized manner by the same surgeon in 18 Dutch Belted pigmented rabbits. After a follow-up of 3 weeks, the rabbits were killed and analyses of the enucleated eyes were performed from the posterior or Miyake-Apple view. The intensity of central PCO, peripheral PCO, and Soemmering's ring formation was scored from 0 to 4. The area of Soemmering's ring formation was also scored from 0 to 4 based on the number of quadrants involved. Other parameters analyzed were capsulorhexis coverage of the IOL anterior surface, IOL centration, fixation, and presence of striae. Results from the posterior view were complemented by histopathologic evaluation of the eyes. No statistically significant difference was found between the 4 groups of IOLs in the parameters analyzed from the posterior view. When cell ingrowth occurred with the 1-piece designs, causing peripheral and central PCO formation, it was more likely to start at the optic-haptic junctions, as observed during the clinical follow-up with slitlamp examination and confirmed by gross and histopathologic analyses of the enucleated eyes. The square, truncated optic edge is the most important IOL design feature for PCO prevention. The optic-haptic junctions of the 1-piece designs appear to be sites where the barrier effect of the truncated optic edge is less effective.

Posterior capsule opacification in rabbit eyes implanted with hydrophilic acrylic intraocular lenses with enhanced square edge

Purpose: To evaluate the development of posterior capsule opacification (PCO) after implantation of single-piece hydrophilic acrylic intraocular lenses (IOLs) with an enhanced square edge. Setting: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Methods: The standard 570H Centerflex (Rayner Ltd.) design was compared to 2 new designs with enhanced square edges: the 570E and the 570C. Ten IOLs of each type were implanted in a randomized manner by the same surgeon in 15 pigmented rabbits. After a follow-up of 3 weeks, the rabbits were killed and the eyes were analyzed from the posterior view. The intensity of central PCO, peripheral PCO, and Soemmering's ring formation was graded from 0 to 4. The area of Soemmering's ring was graded from 0 to 4 based on the number of quadrants involved. Other parameters analyzed were capsulorhexis coverage of the IOL edge and IOL centration and fixation. Results from the posterior view were complemented by histopathological evaluation. Results: Posterior capsule opacification was lowest in the 570C group, highest in the 570H group, and intermediate in the 570E group. There was a statistically significant difference between the 3 groups in peripheral PCO ( P = .039). No significant difference was found between the groups in the other parameters analyzed. When cell ingrowth occurred with the 570H, it started at the optic–haptic junctions, as observed during the clinical follow-up and confirmed by gross and histopathological analyses. Conclusions: The square optic edge is the most important IOL design feature for PCO prevention. However, it should be present for 360 degrees around the IOL optic to provide an effective barrier effect.

Effect of a silicone intraocular lens with a sharp posterior optic edge on posterior capsule opacification

Purpose: To compare the inhibiting effect on posterior capsule opacification (PCO) of a silicone intraocular lens (IOL) with a sharp posterior optic edge (ClariFlex OptiEdge®, Advanced Medical Optics) and a silicone IOL with a round optic edge (PhacoFlex SI-40, Advanced Medical Optics). Setting: Department of Ophthalmology, University of Vienna, Vienna, Austria. Methods: This prospective randomized patient- and examiner-masked study comprised 104 eyes of 52 patients with bilateral age-related cataract. All patients had cataract surgery in both eyes and received a sharp-edged IOL in 1 eye and a round-edged IOL in the other eye. Postoperative examinations were at 1 week, 1 and 6 months, and 1 year. Digital slitlamp and retroillumination images were taken of each eye. The amount of PCO was assessed subjectively at the slitlamp and objectively using Automated Quantification of After-Cataract (AQUA) automated-image analysis software. Results: The sharp-edged IOL group had significantly less regeneratory and fibrotic PCO 1 month, 6 months, and 1 year after surgery. The mean AQUA PCO score (scale 0 to 10) was 0.71 in the sharp-edged IOL group and 1.40 in the round-edged IOL group ( P<.001). The sharp-edged IOL group had less peripheral fibrotic PCO. There was no significant difference between the 2 IOL groups in patient reports of edge glare. Conclusion: The sharp-edged design of the ClariFlex OptiEdge silicone IOL led to significantly less PCO than the round-edged PhacoFlex SI-40 IOL 1 year postoperatively.

Journal of Cataract and Refractive Surgery

Purpose: To evaluate the role of posterior optic edge design and the effect of anterior capsule polishing on peripheral fibrotic posterior capsule opacification (PCO).Setting: Department of Ophthalmology, University of Vienna, Vienna, Austria.Methods: This randomized prospective study comprised 144 eyes of 72 patients with bilateral age-related cataract. Each patient had standardized cataract surgery in both eyes by the same surgeon. Group 1 (46 patients) received a round-edged hydrophobic acrylic IOL (AMO Sensar® AR40) in 1 eye and a sharp-edged hydrophobic acrylic IOL (AMO Sensar® OptiEdge AR40e) in the other eye. Group 2 (26 patients) received a silicone IOL (Pharmacia CeeOn® 911A) with a truncated optic in both eyes. In this group, the anterior capsule was extensively polished in 1 eye and was left unpolished in the other eye. Digital slitlamp photographs were taken 1 year postoperatively using a standardized photographic technique for fibrotic PCO. The intensity of PCO was subjectively graded (score 0 to 4) by 2 masked examiners.Results: Subjective PCO scores correlated well between the 2 examiners (r = 0.88). In Group 1, the mean PCO score was 0.26 for the OptiEdge AR40e IOL and 0.90 for the AR40 IOL (P<.01). In Group 2, the mean PCO score was 0.24 in eyes with a polished capsule and 0.17 in eyes in which the capsule was not polished (P = .31).Conclusions: The sharp-edged OptiEdge AR40e IOL led to significantly less peripheral fibrotic PCO 1 year postoperatively than the round-edged AR40 IOL. In eyes with the sharp-edged silicone 911A IOL, anterior capsule polishing caused no significant difference in fibrotic PCO.

Anterior capsule relationship of the AcryS of intraocular lens optic and posterior capsule opacification: A prospective randomized clinical trial

Objective To evaluate the relationship of the anterior capsule and the AcrySof MA30BA intraocular lens (IOL) and its impact on the development of central posterior capsule opacification (PCO). Design Prospective, randomized, controlled trial. Participants Two hundred two patients with senile cataracts received an AcrySof IOL between July and December 1998 at Iladevi Cataract and IOL Research Center, Ahmedabad, India. Intervention Patients were randomized prospectively to receive 1 of the 3 possibilities of anterior capsule and IOL optic relationship: group 1, total anterior capsule cover (360°) of the optic; group 2, no anterior capsule cover (360°) of the optic; group 3, partial anterior capsule cover (<360°) of the optic. After surgery, slit-lamp video photography was performed every 6 months for 3 years. Analyses of variance and chi-square tests were used to compare treatment groups. Main outcome measures Incidence of PCO in the 3 groups. The posterior capsule was divided into 3 zones: peripheral, central 3 mm, and midperipheral (the space between the peripheral and the central zones). Results The average follow-up was 35.3 ± 1.52 months in all the groups. At 3 years, the rate of central PCO was 6.4% in group 1, 7.1% in group 2, and 5.9% in group 3 ( P = 0.9). Midperipheral PCO was present in 24.2% in group 1, 16% in group 2, and 20.6% in group 3 ( P = 0.9). Peripheral PCO was seen in 100% of patients in all groups. The neodynium:yttrium–aluminum–garnet laser (Nd:YAG) posterior capsulotomy rate was 0% in all groups. Conclusions There was no significant difference in the incidence of development of central PCO among the 3 groups. No patient experienced central PCO that required Nd:YAG capsulotomy. When using the AcrySof IOL model MA30BA, the relationship of the anterior capsule and the IOL does not seem to be a factor that relates to the development of central PCO.

Influence of optic edge design and anterior capsule polishing on posterior capsule fibrosis

Purpose: To evaluate the role of posterior optic edge design and the effect of anterior capsule polishing on peripheral fibrotic posterior capsule opacification (PCO). Setting: Department of Ophthalmology, University of Vienna, Vienna, Austria. Methods: This randomized prospective study comprised 144 eyes of 72 patients with bilateral age-related cataract. Each patient had standardized cataract surgery in both eyes by the same surgeon. Group 1 (46 patients) received a round-edged hydrophobic acrylic IOL (AMO Sensar ® AR40) in 1 eye and a sharp-edged hydrophobic acrylic IOL (AMO Sensar ® OptiEdge AR40e) in the other eye. Group 2 (26 patients) received a silicone IOL (Pharmacia CeeOn ® 911A) with a truncated optic in both eyes. In this group, the anterior capsule was extensively polished in 1 eye and was left unpolished in the other eye. Digital slitlamp photographs were taken 1 year postoperatively using a standardized photographic technique for fibrotic PCO. The intensity of PCO was subjectively graded (score 0 to 4) by 2 masked examiners. Results: Subjective PCO scores correlated well between the 2 examiners ( r = 0.88). In Group 1, the mean PCO score was 0.26 for the OptiEdge AR40e IOL and 0.90 for the AR40 IOL ( P<.01). In Group 2, the mean PCO score was 0.24 in eyes with a polished capsule and 0.17 in eyes in which the capsule was not polished ( P = .31). Conclusions: The sharp-edged OptiEdge AR40e IOL led to significantly less peripheral fibrotic PCO 1 year postoperatively than the round-edged AR40 IOL. In eyes with the sharp-edged silicone 911A IOL, anterior capsule polishing caused no significant difference in fibrotic PCO.

Influence of intraocular lens material on regeneratory posterior capsule opacification after neodymium:YAG laser capsulotomy

Purpose To evaluate the influence of a neodymium:YAG (Nd:YAG) laser capsulotomy on the morphology and development of regeneratory opacification of the remaining surrounding posterior capsule. Setting Department of Ophthalmology, Medical School, University of Vienna, Vienna, Austria. Methods Standardized digital retroillumination photographs were taken immediately before and after Nd:YAG laser capsulotomy and at 1 week, 6 months, and 1 to 3 years in 38 eyes of consecutive patients. Changes in regeneratory posterior capsule opacification (PCO) and opacification around the capsulotomy opening were evaluated. The influence of the type of intraocular lens (IOL) material and design (acrylic, n = 8; hydrogel, n = 8; silicone open loop, n = 11; silicone plate haptic, n = 6; poly(methyl methacrylate) [PMMA], n = 5) was assessed. The state of the anterior vitreous surface was examined at the slitlamp in all eyes. Results In 8 of 17 eyes with a silicone IOL, reduced regeneratory PCO was observed. Massive pearl formation on the margin of the Nd:YAG capsulotomy was typical with silicone IOLs (8 eyes) but also occurred with PMMA IOLs. Eyes with acrylic IOLs had no change in regeneratory PCO after the capsulotomy. Three of 8 eyes with hydrogel IOLs had complete closure of the posterior capsulotomy opening. Conclusions Neodymium:YAG laser capsulotomy induced changes in the development and morphology of regeneratory PCO. Silicone and PMMA IOLs led to significant pearl formation on the capsulotomy margin, often combined with a reduction of peripheral regeneratory PCO (silicone). Hydrogel IOLs led to a higher incidence of reclosure of the Nd:YAG capsulotomy opening.

Implantation of a single-piece, hydrophilic, acrylic, minus-power foldable posterior chamber intraocular lens in a rabbit model: Clinicopathologic study of posterior capsule opacification

Purpose To compare the extent of posterior capsule opacification (PCO) after implantation of a standard-power biconvex Centerflex® intraocular lens (IOL) and a newly introduced biconcave high-minus-power Centerflex design in rabbit eyes. Setting The Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, and the David J. Apple, MD, Laboratories for Ophthalmic Devices Research, John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City, Utah, USA. Methods Twelve rabbits had phacoemulsification and implantation of 2 foldable single-piece hydrophilic acrylic Centerflex posterior chamber IOLs. The right eyes received a standard-power (+21.00 diopters [D]) biconvex-optic lens and the left eyes, a minus-power (–7.00 D) biconcave-optic IOL. Formation of PCO was evaluated 3 weeks after surgery using the Miyake-Apple posterior photography technique. Histological sections from each globe were prepared to analyze capsular bag status and assess postsurgical intracapsular lens epithelial cell (LEC) proliferation, especially ingrowth of LECs across the visual axis. The data were analyzed using the Kruskal-Wallis 1-way analysis of variance for nonparametric measurements and the Mann-Whitney rank sum test. Results There was no significant difference in Soemmering's ring formation between the 2 IOL models. The biconcave minus-power IOL showed significantly lower central and peripheral PCO scores than the biconvex standard-power lens ( P<.05). Pathological evaluations revealed that the effective site of blockage of LECs was at the truncated optic edge of both lenses, even in the presence of retained and/or regenerative cortical material. Conclusions This study confirms the efficacy of a truncated IOL optic in helping reduce the incidence of PCO. Both IOL designs have optic geometries that create clear-cut barrier effects. However, the biconcave minus-power IOL, which has a thicker, square, truncated optic edge with a ridge that encircles the periphery of the optic for 360 degrees, appears to have an enhanced barrier effect, especially at the optic–haptic junction. This further minimizes the ingrowth of migrating LECs toward the visual axis.

Effect of haptic angulation on posterior capsule opacification in modern foldable lenses with a square, truncated optic edge

Purpose: To analyze the effect of different haptic angulations on posterior capsule opacification (PCO) in a modern foldable intraocular lens (IOL) with a square-edged optic designed to reduce the incidence of PCO. Setting: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. Methods: Ten Dutch Belted, serum Pasteurella-free pigmented rabbits of the same age and sex had bilateral phacoemulsification with endocapsular IOL implantation. The eyes were implanted with Centerflex® IOLs (Rayner) with haptic angulations of 0 degree (n = 8), 5 degrees (n = 4), 10 degrees (n = 4), or 15 degrees (n = 4). Results: There was no statistical difference in central PCO, peripheral PCO, and measured IOL decentration among the angulation groups. Conclusion: With the Centerflex IOL, haptic angulation did not seem to be a significant factor influencing PCO. It appears that the barrier effect of the IOL’s truncated, square-edged optic overrides the angulation factor in preventing PCO.