Optimization of Contact Lenses for Corneal Protection During Vitreoretinal Surgery

OBJECTIVES To optimize parameters of contact lenses (CLs) and evaluate their ability to protect the cornea during vitreoretinal surgery. METHODS We compared the protective effects of balanced saline solution, viscoelastic agent, and CLs on rabbit corneas under conditions simulating vitreoretinal surgery. We evaluated CLs of different thicknesses and compared the protective effects of polymethyl methacrylate (PMMA) and gas-permeable fluorosilicone acrylate (XO) lenses on the corneas of rabbits and patients with severe proliferative diabetic retinopathy (PDR). The corneal fluorescein staining score (FSS) was measured to compare the protective effects of CLs. RESULTS The FSS was significantly lower in the PMMA group than in the balanced saline solution and viscoelastic agent groups. The thickness of the PMMA lenses had no significant effect on the FSS. The FSS was significantly higher in the PMMA group than in the XO group. In patients with PDR, on day 1 after vitreoretinal surgery, the FSS was significantly higher in the PMMA group than in the XO group, although no significant difference was observed on postoperative day 7. CONCLUSION The XO lens offers better corneal protection during noncontact wide-angle vitreoretinal surgery and protects the corneal epithelium more efficiently during vitrectomy in patients with PDR, irrespective of its thickness.