Indian Journal of Ophthalmology (Jan 2000)
The role of central corneal thickness in the diagnosis of glaucoma
Abstract
Purpose: To determine the effect of central corneal thickness (CCT) on applanation tonometry and any resultant misclassification of normals as ocular hypertension. Method: The central corneal thickness was measured using the ultrasound pachometer in 50 normals, 25 glaucoma and 23 ocular hypertensive patients. The student′s "t" test was used to determine any significant difference in CCT between the three groups. Results: There was a statistically significant difference in the mean CCT of the ocular hypertensives ( 0.574 + 0.033mm) as compared to the glaucomas (0.534 ± 0.030mm) and normals (0.537 ± 0.034mm). Applying the described correction factor for corneal thickness, 39% of eyes with ocular hypertension were found to have a corrected IOP of 21mmHg or less. Conclusions: Increased corneal thickness in ocular hypertension may lead to an overestimation of IOP in 39% of cases. Measurement of central corneal thickness is advisable when the clinical findings do not correlate with the applanation IOP.
