Effect of ophthalmic viscosurgical devices on lens epithelial cells: a morphological study.

PURPOSE

To investigate the morphological effects of Viscoat (sodium hyaluronate 3.0%-chondroitin sulfate 4.0%) on lens epithelial cells (LECs).

SETTING

Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, USA, and the Laboratory of Ultrastructural Morphology, Zoological Institute, University of Liège, Liège, Belgium.

METHODS

Human LECs collected via capsulorhexis were examined by light microscopy (LM) and transmission electron microscopy (TEM). Lens epithelial cells from rabbit capsulorhexis samples were studied by LM and TEM following exposure to Provisc (sodium hyaluronate 1.0%) or Viscoat ophthalmic viscoelastic device (OVD). Since Viscoat is hypertonic (340 mOsm), hypertonic, isotonic, and hypotonic solutions were compared to investigate a possible mechanism for the observed effects. The effects of Provisc and Viscoat on rabbit LECs in the intact lens were also compared.

RESULTS

Human LECs gathered via capsulorhexis following exposure to Viscoat were generally thinner than control samples and often had condensed nuclei and increased intracellular vacuolization. Rabbit capsular tissue exposed in situ to Viscoat demonstrated changes similar to those seen in humans. Cells exposed to Provisc were similar to cells in untreated controls in humans and rabbits. Corneal endothelial cells exposed to either agent were unaffected. Experiments with hypertonic and hypotonic buffers induced some of the changes noted with Viscoat, but the effects were less severe. Lens epithelial cells in intact rabbit lenses exposed to Viscoat appeared similar to LECs in the control samples.

CONCLUSIONS

Light microscopy and TEM of human lens capsule tissue suggest that Viscoat induces significant morphological changes in LECs during cataract surgery. The changes may underlie the improved visualization of these cells that has been reported during cataract surgery. Corneal endothelial cells were unaffected by exposure to Viscoat. Studies in a rabbit model suggest that the hyperosmolarity of Viscoat may play a partial role in the LEC changes.