[Analysis of intraocular pressure and corneal thickness after laser in situ keratomileusis]

Abstract

Objective: To analyze the changes and relationship of the intraocular pressure (IOP) and the corneal thickness (CT) after laser in situ keratomileusis (LASIK).

Methods: This prospective study comprised two groups: noncontact tonometer group 221 eyes (156 patients) 1 month after LASIK and 72 eyes (50 patients) 3 months after LASIK; Goldmann applanation tonometer group 60 eyes (36 patients) 1 month after LASIK. The spherical equivalent, the corneal thickness and the IOP readings were measured pre- and post-LASIK.

Results: The CT was thicker than the predicted value and it was much more prominent in the higher myopic group with more regression degree of refraction. The CT at postoperative 3 month was thicker than that at 1 month. There was a statistical decrease in mean tonometer readings, both with non-contact tonometer and Goldmann applanation tonometer; and there was statistically significant correlation between the changes of central corneal thickness and the changes of non-contact tonometer readings (r = 0.2, P < 0.002). The IOP decrease with Goldmann applanation tonometer was less than that with noncontact tonometer.

Conclusions: The actual ablation depth of cornea is lower than the predicted. The IOP readings of the patients after LASIK are lower than the real IOP values. Further efforts should be made to improve the accuracy. Goldmann applanation tonometer is a better choice measuring IOP after excimer photoablative corneal refractive surgery.