PURPOSE: To determine if at clinical dosages, the topical nonsteroidal anti-inflammatory drugs diclofenac and ketorolac decrease corneal sensitivity, and if there is a difference in discomfort on instillation. METHODS: In a double-masked study, 30 patients were randomized to receive two of three topical drops, Endosol, diclofenac sodium, and ketorolac tromethamine. A microaesthesiometer was used to evaluate corneal sensation. Baseline corneal sensitivity was obtained on each patient. Corneal sensory thresholds were remeasured at 7 and 15 minutes following eyedrop application. Patients also completed a questionnaire that graded the burning caused by the medications. RESULTS: No significant decrease in corneal sensory thresholds was found with diclofenac or ketorolac compared with control at baseline (P = .50), 7 minutes (P = .41), or 15 minutes (P = .82). There was significantly more burning with diclofenac and ketorolac compared to control. There was a small but not statistically significant (P = .28) trend of more burning with ketorolac than diclofenac. CONCLUSION: Neither diclofenac nor ketorolac were found to decrease corneal sensation compared to control. There was no significant difference in burning upon instillation reported by patients.