Corneal Wound Healing after Excimer Laser Ablation: Effects of Nitrogen Gas Blower

Purpose: To examine the effects of blowing nitrogen gas over the cornea during photorefractive keratectomy. Methods: Excimer laser ablations for myopia were performed on rabbit corneas with or without the blowing of nitrogen across the surface of the cornea. All eyes underwent a 5-diopter myopic ablation; in 8 eyes, a ring was used to blow nitrogen gas across the cornea, and, in 8 eyes, the same ring was used, but no nitrogen gas was blown. Results: Epithelial healing occurred more rapidly in the eyes that were not treated with the gas (3.8 ± 1.3 days) than in the gas-treated group (6.1 ± 0.8 days; P = 0.0025). Corneal haze was greater in the group treated with gas. Results of histologic examination showed the ablated area to have a smoother surface when nitrogen was not blown across the cornea surface. Conclusion: Superficial corneal deturgescence produced by the nitrogen gas appears to result in a rougher surface immediately postoperatively with undesirable effects on surface healing, but further studies will be necessary to determine the applicability of these results to humans.