Comparison of Central Corneal Thickness and Retinal Nerve Fiber Layer Thickness and Ganglion Cell Complex in Patients with Ocular Hypertension

Purpose: To evaluate the correlation of retinal nerve fiber layer thickness (RNFLT) with ganglion cell complex and central corneal thickness (CCT) measurements in patients with ocular hypertension and healthy subjects. Material and Method: Seventy-six eyes of 38 patients with ocular hypertension and 76 eyes of 38 healthy subjects were included in this study. Both groups were stratified by CCT into <550 mu m, 550-579 mu m, and >= 580 mu m corneal subsets. Ultrasonic pachimetry was used to measure CCT, and spectral OCT was used to measure RNFLT (average, superior average, inferior average) and ganglion cell complex. Results: CCT and retinal nerve fiber layer (average, superior average, inferior average) measurements were compared in each groups. CTT measurements in the ocular hypertension group were higher when compared with those in the control group. Superior quadrant RNFL was thinner in cases with CCT <550 mu compared to cases with CCT 550-579 mu m and >579 mu m (p<0.01). Superior quadrant RNFL in cases with CCT 550-579 mu m was thinner than in cases with >= 580 mu m (p<0.01). In the ocular hypertension group, there was no significant correlation of CCT with mean RNFLT and inferior quadrant RNFLT measurements (p>0.05). In the control group, there was no significant correlation between CCT and RNFLT (average, superior average, inferior average) measurements (p>0.05). There was no significant correlation between CCT and average, superior average, inferior average ganglion cell complex in both groups. Discusion: Ocular hypertension patients with CCT <550 mu m may represent patients who have very early undetected glaucoma. This may in part explain the higher risk of these patients for progression to glaucoma.