Normal-tension glaucoma and central corneal thickness.

PURPOSE: To determine whether a decreased corneal thickness is a primary factor in the lower intraocular pressure readings found in normal-tension glaucoma patients.

METHODS

Fourteen patients with normal-tension glaucoma were compared with 14 age- and sex-matched glaucoma patients. Corneal thickness was measured by ultrasonic pachymetry on each eye.

RESULTS

The corneal thickness (mean +/- SD) in patients with normal-tension glaucoma was 0.536 +/- 0.035 mm. The corneal thickness in patients with glaucoma was 0.537 +/- 0.035 mm. The 95% confidence interval for the difference between the two groups was -0.027 to +0.027 mm.

CONCLUSION

It has been documented that increased corneal thickness leads to high readings of intraocular pressure. Therefore, decreased corneal thickness may lead to a lower intraocular pressure reading. This study suggests that for most normal-tension glaucoma patients corneal thickness is not a major factor in accounting for the lower intraocular pressure measurements when compared with primary open angle glaucoma patients.