Increased corneal thickness in patients with ocular hypertension.

BACKGROUND Central corneal thickness greater than 0.520 mm causes true intraocular pressure to be overestimated when the technique of applanation tonometry is used to measure intraocular pressure. OBJECTIVE To compare the corneal thickness measurements of patients enrolled in a study of ocular hypertension with those of age-matched control subjects with normal intraocular pressure. METHODS Central corneal pachymetry using an optical pachymeter was performed on each study subject (n = 55) at baseline and in an independent sample of control subjects. A 2 sample, 2-tailed T test was used to compare the 2 populations. RESULTS The patients with ocular hypertension had significantly higher mean corneal thickness measurements (mean +/- SD, 0.594 +/- 0.037 mm) than the control group (0.563 +/- 0.027 mm) (P<.001). CONCLUSION Corneal thickness may be a confounding factor in the measurement of intraocular pressure, and this may modify the risk for progression to glaucoma in patients with ocular hypertension.