LASIK does not affect IOP readings in mild, moderate myopes

NEW HAVEN, Conn. — LASIK did not cause significant intraocular pressure changes in patients with mild to moderate myopia, according to Roya Vakili, MD, and colleagues. These findings are in contrast to earlier reports of significant reductions in measured IOP after LASIK surgery for high myopia.

The study authors suggest that further study is needed to determine if there is a critical amount of corneal change needed to effect a significant change in IOP.

Dr. Vakili and colleagues here at Yale-New Haven Eye Laser Center obtained preoperative and postoperative IOP measurements on 66 eyes of 34 patients undergoing LASIK. Patients had a mean preop refractive error of –5.66 D.

The researchers took IOP measurements with Goldmann applanation tonometry, Tono-Pen and pneumatonometry. Central corneal thickness, keratometric and astigmatic measurements were also taken preop and postop.

Linear regression was used to correlate IOP measurements with degree of myopia corrected, astigmatism and central corneal thickness both before and after LASIK.

The reduction in central corneal thickness after LASIK was statistically significant (P < .0001). Neither Goldmann tonometry nor Tono-Pen measurement showed a statistically significant change in mean IOP after LASIK. Pneumatonometry showed a small but statistically significant decrease in IOP.

The study is published in the Journal of Glaucoma.