SCHIRMER TEST VALUES AND THE OUTCOME OF PHOTOREFRACTIVE KERATECTOMY

Purpose: To evaluate whether relative tear deficiency, indicated by lo w standardized Schirmer test values, influences the outcome of photore fractive keratectomy (PRK). Setting: Department of Ophthalmology, Univ ersity of Helsinki, Finland. Methods: Sixty-two patients were pair-mat ched by age and attempted myopic correction. They were divided into tw o groups: Group 1 (n = 31) comprised patients with standardized, eye-c losed Schirmer test values of less than or equal to 6 mm/5 min; Group 2 (n = 31), patients with Schirmer test values of greater than or equa l to 10 mm/5 min. None of the eyes showed clinical signs of dry eye on slitlamp examination. Follow-up was 12 months. Results: At 1 year, th e visual acuity was 0.5 or better in 68.4% of Group 1 eyes and in 78.9 % of Group 2 eyes. In Groups 1 and 2, 55.6% of eyes and 52.6%, respect ively, were within 0.50 diopter (D) of attempted correction and 83.3% and 89.5%, respectively, were within 1.00 D. At 6 months, the mean ove rcorrection was +1.32 +/- 1.13 D in Group I and +0.77 +/- 0.57D in Gro up 2 and at 1 year, +0.96 +/- 1.13 D and +0.58 +/- 0.37 D, respectivel y. There was no difference between the two groups in visual acuity and obtained refractive correction or haze score at any postoperative exa mination. The minor tendency toward overcorrection in Group I could no t be confirmed statistically. Conclusion: Subclinical tear deficiency indicated by low Schirmer test values did not influence the PRK outcom e in patients matched by age and magnitude of refractive correction.