Tear secretion following spherical and astigmatic excimer laser photorefractive keratectomy

To evaluate the effect of spherical and astigmatic excimer laser photorefractive keratectomy (PRK and PARK, respectively) on tear secretion.

The Vlemma Eye Center, Athens, Greece.

Forty-eight eyes of 48 patients had PRK (28 eyes) or PARK (20 eyes) for the correction of myopia and combined myopic astigmatism. The fellow eye served as a control. The mean preoperative spherical equivalent was -3.96 diopters (D) +/- 1.00 (SD) in the PRK eyes (range -2.00 to -6.50 D) and -3.45 +/- 0.50 D in the PARK eyes (range -1.75 to -6.00 D). Attempted correction aimed at emmetropia. Schirmer I and II and tear film breakup time (BUT) tests were performed preoperatively and 1, 3, and 6 months postoperatively. All tests were correlated to the amount of attempted correction.

In the PRK group, the preoperative mean values were Schirmer I, 16.20 mm; Schirmer II, 12.73 mm; and BUT, 16.46 sec. At 1 month, they were 12.23 mm, 8.46 mm, and 13.33 sec, respectively; at 3 months, 13.86 mm, 10.64 mm, and 14.42 sec, respectively; at 6 months, 14.32 mm, 11.32 mm, and 15.36 sec, respectively. In the PARK group, the mean Schirmer I, II, and BUT values were preoperatively 18.52 mm, 14.86 mm, and 17.42 sec, respectively; at 1 month, 14.5 mm, 10.4 mm, and 14.36 sec, respectively; at 3 months, 15.36 mm, 11.81 mm, and 14.72 sec, respectively; and at 6 months, 16.5 mm, 12.15 mm, 16.5 sec, respectively. No correlation to the amount of attempted correction was found. Fellow-eye tests were not affected at any interval.

In the first 6 months after PRK and PARK, tear secretion test values decreased.