Changes in intraocular pressure after laser in situ keratomileusis for myopia, hyperopia, and astigmatism.

Abstract

Reports have shown that photorefractive keratectomy changes intraocular pressure (IOP) in myopic eyes by changing the thickness and curvature of the cornea. Changes in intraocular pressure after laser in situ keratomileusis (LASIK) for hyperopia led the authors to evaluate IOP after LASIK for various refractive errors. The measurement of intraocular pressure with a Goldman applanometer in the central cornea was evaluated before and 3 months after LASIK in 100 eyes of 55 patients with various refractive errors. Corneal thickness (pachymetry) and corneal topography were evaluated. After LASIK, a significant decrease of intraocular pressure was observed in most eyes: mean 11.9 +/- 3.2 mmHg before and 9.8 +/- 2.6 mmHg at 3 months after surgery (P < .001). Mean decrease in IOP was 2.75 +/- 3.3 mmHg (P < .0001) for myopic eyes, 2.28 +/- 2.43 mmHg (P < .001) for hyperopic eyes, and 1.47 +/- 2.5 mmHg (P < .0012) for astigmatic eyes. IOP reduction was not significantly correlated to the amount of ablation (r = 0.05) or to corneal thickness. Intraocular pressure decreased in myopic, hyperopic, and astigmatic eyes after LASIK. The reduction was not correlated to the amount of tissue removed or to flattening or steepening of the central cornea.