Corneal endothelial protection by different viscoelastics during phacoemulsification

PURPOSE: To evaluate corneal endothelium morphology and function after phacoemulsification using different viscoelastics. SETTING: Eye Clinic, University of Trieste, Italy. METHODS: This prospective, randomized study included results of preoperative and postoperative (7, 30, and 90 days) examinations of 66 patients scheduled for phacoemulsification without ocular pathology; 8 patients were excluded. Patients were randomly assigned to one of four groups based on type of viscoelastic used: 1% sodium hyaluronate (Healon); 1.4% sodium hyaluronate (Healon GV); 4% sodium chondroitin sulfate-3% sodium hyaluronate (Viscoat); 2% hydroxypropyl methylcellulose (Hymecel). Mean cell density and cell size variation coefficient were determined by specular microscopy; central corneal thickness, by ultrasonic pachymetry; and endothelial permeability coefficient and active pump function, by anterior segment fluorophotometry. RESULTS: There were no significant differences in postoperative mean cell loss among the groups. The cell size variation coefficient was altered in all groups 7 days after surgery and was still impaired at 30 days in the Hymecel group. A significant increase in mean corneal thickness, endothelial permeability, and active pump function occurred in the Healon and Hymecel groups 7 days after surgery. These parameters were still altered 30 days after surgery in the Hymecel group. Endothelial functional alterations did not occur in the Healon GV or Viscoat group. CONCLUSION: Viscoat and Healon GV are effective in minimizing functional damage of endothelial structure in the early medium-term postoperative period.