Phototherapeutic smoothing as an adjunct to photorefractive keratectomy inporcine corneas

PURPOSE: To study the smoothing effect of phototherapeutic keratectomy (PTK ) using masking fluids as an adjunct to standard photorefractive keratectom y ablations. METHODS: Six fresh porcine corneas underwent -6.00, -10.00, and -15.00 D sp here ablations using the VISX Star excimer laser. Multizone treatments to a maximum 6.5 mm radially symmetrical bed were used with a fluence of 160 mJ /cm(2). Three of the treatments were supplemented with a thin layer of bala nced salt solution and 6 mu m of full beam PTK. The corneas were examined b y electron microscopy. RESULTS: Smoother treatment zones were apparent in corneas undergoing PTK f ollowing PRK. The effect was more marked at higher dioptric ablations, CONCLUSION: PTK may improve surface smoothness after PRK, especially for hi gher dioptric ablations.