In situ ablation of lens epithelial cells in porcine eyes with the laser photolysis system

Evaluation of laser capsule polishing for prevention of posterior capsule opacification in a human ex vivo model

PURPOSE

To evaluate the efficacy of a laser photolysis (LP) system in preventing posterior capsule opacification (PCO) in a human ex vivo PCO model.

SETTING

Ars Ophthalmica Study Center, Department of Ophthalmology, General Hospital Linz, Medical Faculty of Johannes Kepler University, Linz, Austria, and the Department of Ophthalmology, Ludwig-Maximillians-University, Munich, Germany.

DESIGN

Prospective randomized controlled laboratory trial.

METHODS

Open sky extracapsular cataract extraction following implantation of a capsular tension ring (CTR) into the capsular bag was performed in 28 human donor eyes. Donor eyes received LP treatment of the capsular bag fornix and the anterior capsule for 180 or 360 degrees, whereas the contralateral eyes served as a control group. Lens epithelial cell (LEC) growth onto the posterior capsule was determined objectively during 3 months of organ culture incubation.

RESULTS

The mean interval until a complete monolayer of LECs on the posterior capsule had formed was 8.2 days ± 1.2 (SD) for control eyes and 9.4 days ± 1.1 for eyes with 180-degree LP treatment (P = .042). Eyes with 360-degree treatment showed no sign of LEC growth or migration onto the posterior capsule during the entire observation period. Transmission light microscopy revealed many residual LECs on the anterior lens capsule of untreated areas, whereas no evidence of remaining LEC in areas treated with LP was found.

CONCLUSIONS

This study demonstrates complete and sustained PCO prevention by a prototype LP system in a capsular tension ring-based human ex vivo model. Laser capsule polishing has the potential to serve as a successful surgical strategy for PCO prevention.

FINANCIAL DISCLOSURE

The authors have no proprietary or financial interest in any of the materials or equipment mentioned in this study.

Ablation of lens epithelial cells with a laser photolysis system: histopathology, ultrastructure, and immunochemistry

PURPOSE

To evaluate efficacy of a neodymium:YAG (Nd:YAG) laser photolysis system in removing lens epithelial cells (LECs) and characterize the effect of the laser on laminin and fibronectin involved in LEC adhesion and migration.

METHODS

Cadaver eyes were evaluated using the Miyake technique. The lenses were removed with phacoemulsification. The modified Nd:YAG laser was used to clean the LECs from the capsule. Only the fornix was cleaned in some eyes and the anterior subcapsular area in other eyes. Some areas were not treated and acted as controls. Standard irrigation/aspiration (I/A) removal of LECs was performed in additional eyes. The eyes were analyzed using light microscopy and immunohistochemical staining.

RESULTS

Histopathologic evaluation showed that the laser removed the LECs from the anterior lens capsule and from the fornix. Immunohistochemical staining showed fibronectin and laminin staining in the untreated areas that was absent in the treated areas. Standard I/A removal of the LECs showed absence of cells but persistent laminin and fibronectin. Electron microscopy showed epithelial cells in untreated areas with an absence of the LECs and debris in treated areas.

CONCLUSIONS

The laser photolysis system removed LECs from the anterior lens capsule and capsule fornix. Along with the cells, laminin, fibronectin, and cell debris remained in the untreated areas but were removed by the treatment. This treatment may be useful in preventing posterior capsule opacification.