Purpose: To evaluate the usefulness of viscoelastic in protecting the corneal endothelium from desiccation injury associated with fluid-air exchange in a rabbit model.
Design: Experimental study.
Methods: Rabbit eyes undergoing pars plana lensectomy and vitrectomy were insufflated with either dry or humidified air for 20 minutes following introduction of either Opegan (sodium hyaluronate 1.0%; Santen, Osaka, Japan) or Viscoat (sodium hyaluronate 3%-chondroitin sulfate 4%; Alcon, Tokyo, Japan) into the anterior chamber. In two other groups of rabbit eyes, the same procedure was performed without using any viscoelastic agent. Corneas obtained from rabbits undergoing surgery were compared with corneas obtained from rabbits not undergoing surgery. Potential alterations in the corneal endothelium were investigated by scanning electron microscopy, by Phalloidin-FITC staining of actin and by in vitro measurements of corneal permeability for carboxyfluorescein using a diffusion chamber.
Results: Scanning electron microscopy displayed less distortion of corneal endothelium with Opegan and Viscoat compared with the dry air-only exposed corneas. Using humidified air in Opegan and Viscoat coated corneas maintained the normal actin cytoskeleton during fluid-air exchange. Paracellular leakage was much less with Opegan and Viscoat use following infusion of dry air comparing to that of dry air-only group (P =.026 and P =.041). The difference was much more striking following humidified air infusion in Opegan or Viscoat coated corneas comparing to dry air-only infused corneas (P <.002 and P <.002).
Conclusions: Coating of rabbit corneal endothelium with Opegan or Viscoat before fluid-air exchange largely prevents dry air damage to the endothelium. Infusion of humidified air further protects corneal endothelium during fluid-air exchange in aphakic rabbit eyes.