Interventions for preventing posterior capsule opacification

Posterior capsule opacification (PCO) is the most common long-term complication after cataract surgery with implantation of an intraocular lens (IOL). It can be treated by cutting a hole in the posterior lens capsule with an Nd:YAG laser (Neodymium:YAG laser capsulotomy), however this procedure may lead to other complications. It is also expensive and not available in large parts of the developing world. Therefore, many studies have been performed to investigate the pathogenesis of PCO and to find possible ways of preventing it. This review included 66 prospective, randomised, controlled trials assessing the effect of different interventions on PCO. These 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. All trials had a follow-up time of at least 12 months. The effect of the intervention on PCO was assessed by measuring visual acuity, (subjective or objective) PCO score and the number of performed Nd:YAG laser capsulotomies. The results of the review were divided into three parts. In part one (effect of IOL material on PCO), the meta-analysis of the included trials found no significant differences in the PCO scores between different IOL materials. In part two (effect of IOL geometry), the meta-analysis showed significantly lower PCO rates in IOLs with sharp posterior optic edges than in IOLs with round optic edges. However, there was no difference between 1-piece and 3-piece IOLs. In part three (influence of surgical technique and drugs on PCO), one trial found a lower PCO rate in IOLs placed in the capsular bag compared to IOLs placed in the sulcus. Another study found a lower PCO rate in eyes with a small capsulorhexis compared to a large capsulorhexis. Where drugs were concerned, only treatment with an immunotoxin led to significantly less PCO in two studies. In summary, primarily the choice of the IOL geometry seems to have a significant influence on the development of PCO. Therefore, IOLs with sharp optic edges should be preferred.

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.

Read the full abstract...
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.

Share/Save