Effect of laser in situ keratomileusis on rebound tonometry and Goldmann applanation tonometry

To determine the influence of refractive surgery on intraocular pressure (IOP) measurements obtained using an iCare rebound tonometer and a Goldmann applanation tonometer.School of Optometry, Hong Kong Polytechnic University, Hong Kong, China.Intraocular pressure was measured using the rebound tonometer and applanation tonometer before and 1 month after uneventful LASIK for myopia.The IOP was measured in 96 eyes (96 patients). The preoperative IOP measured by rebound tonometry (mean 16.7 mm Hg +/- 3.0 [SD]) was statistically significantly higher than by Goldmann applanation tonometry (mean 15.4 +/- 2.5 mm Hg) (P<.01, Wilcoxon test). There was no statistically significantly difference in postoperative measurements between the 2 tonometers (mean 11.9 +/- 2.6 mm Hg and 12.0 +/- 2.4 mm Hg, respectively) (P>.05, Wilcoxon test). The mean difference between the 2 tonometers after LASIK was 0.1 +/- 2.1 mm Hg. The 95% limits of agreement ranged from -4.26 to 4.05 mm Hg. The IOP reduction with rebound tonometry was positively correlated with preoperative IOP.There was a greater decrease in IOP measurement after LASIK by rebound tonometry, showing this method was more affected by surgery.