Reliability of intraocular pressure measurements after myopic excimer photorefractive keratectomy

OBJECTIVE: To determine the reliability of intraocular pressure (IOP) measurements by Goldmann applanation tonometry and pneumotonometry in eyes treated with excimer myopic photorefractive keratectomy (PRK). DESIGN: A prospective case series. PARTICIPANTS: Forty consecutive eyes treated with PRK were evaluated. INTERVENTION AND MAIN OUTCOME MEASURES: Central and peripheral corneal Goldmann tonometry and pneumotonometry measurements were done before surgery, at 1 week, and at 1 and 3 months after surgery. RESULTS: The IOP by Goldmann tonometry from the central cornea was significantly lower than the peripheral IOP; however, there was no difference between IOP measured from central and peripheral corneas by pneumotonometry, which, in turn, correlated with peripheral Goldmann measurements. There was a trend, but not a statistically significant correlation, between the spherical equivalent of the treatment and the amount of decrease in central Goldmann IOP. CONCLUSIONS: Pneumotonometry measures the IOP reliably after PRK from all parts of the cornea, whereas central Goldmann tonometry underestimates the IOP by 2.40+/-1.23 mmHg.