PTK with the 193-nm excimer laser is a safe and effective treatment for many superficial diseases of the cornea.

Excimer lasers are now used for corneal surgery; however, the physical processes occurring during photoablation of the cornea are incompletely understood. High speed laser-based photographic arrangement was constructed. The temporal resolution was better than 1 ns. The setup could work as a Schlieren arrangement, which is sensitive to the refractive index change caused by the shock wave propagating in the air above the eye. With minor changes the setup was converted into a shadowgraph, which could detect the ablation plume and the waves propagating on the surface of the eye. Due to the impact of the excimer laser pulse onto the surface of the cornea, a shock wave was generated in the air. The shadowgraph clearly showed the ejection of the ablated cornea. The ejection velocity of the plume was found to be over 600 m/s. It was shown for the first time that the recoil forces of the plume are generating a wave on the surface of the eye. The laser-based high speed photographic arrangement is a powerful arrangement in the study of physical effects occurring during photoablation of the cornea. (Refract Corneal Surg (suppl) 1993;9:S111-S115)

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A 47-year-old man had photorefractive keratectomy (PRK) to correct myopia. Three months after surgery he was slightly overcorrected with +1.25-0.5/170 degrees. He then suffered a gout attack and showed a refraction of +2.5-0.5/4 degrees which decreased to +1.75-0.5 degrees. To reduce this permanent overcorrection we performed mechanical debridement of the corneal epithelium. the patient had haze grade 2-3 after 2 weeks and haze grade 0-1 some 4 months later. The refraction was +1-0.5/25 degrees. This case report indicates that mechanical debridement is able to reduce overcorrection after PRK and bears a risk of haze formation comparable to that associated with PRK.

BACKGROUND: Both the potential analgesic effects and side-effects of topical diclofenac sodium 0.1% are points of interest after excimer laser phototherapeutic keratectomy. METHODS: Excimer laser phototherapeutic keratectomy was performed in 134 eyes of 134 patients. In 65 eyes (65 patients), the effects of topical diclofenac given three times a day for 3 to 4 days were compared to a control group of 69 eyes (69 patients). All patients received paracetamol for systemic analgesia and were patched after surgery until reepithelialization. RESULTS: Twenty-eight patients (43%) of the diclofenac group needed additional systemic analgesics compared to 67 patients (95%) in the control group. Seventy-two hours after surgery we found no significant differences in corneal epithelial wound healing and no severe complications. CONCLUSION: Topical diclofenac sodium reduces postoperative pain in patients after phototherapeutic keratectomy. [J Refract Surg 1996;13:311-313]