Strategies to prevent lens cell growth causing posterior capsule opacification: An in vitro study

Purpose: Posterior capsule opacification (PCO) is the most common complication of modern cataract surgery. We have recently developed an in vitro human capsular bag PCO model which closely mimics the clinical situation. We use this model to investigate strategies to eliminate lens cell growth. Methods: A sham cataract operation was performed on human donor eyes including capsulorhexis (5 or 8mm), nuclear hydroexpression and irrigation with Hartmann's solution (sometimes supplemented with 5mM EDTA). An IOL could be implanted if required. In some cases IOLs were coated with the CaATPase inhibitor thapsigargin. The capsular bag was dissected free, pinned on a plastic dish and incubated with culture medium (EMEM). Observations were by phase microscopy. Results: Increasing capsulorhexis diameter from 5 to 8mm had little effect on the rate of cell coverage of the posterior capsule. EDTA treatment produced upto 80% cell death at surgery, but the surviving cells achieved confluency at a rate comparable to controls. Surface modification of the IOL with thapsigargin inhibited growth and at concentrations >2μM produced total loss of viable cells. Conclusion: Intervention at surgery in the form of increased capsulorhexis or EDTA irrigation were ineffective at preventing PCO. Thapsigargin coating of the IOL provides a more promising strategy.