The measurement of central corneal thickness of normal subjects and glaucomatous patients with optical coherence tomography

Abstract

To evaluate central corneal thickness (CCT) of normal subjects, patients with primary open angle glaucoma (POAG), normal tension glaucoma (NTG) and ocular hypertension (OHT) using optical coherence tomography (OCT). One hundred and forty-three eyes of 143 normal subjects, 36 eyes of 36 patients with POAG, 39 eyes of 39 patients with NTG and 40 eyes of 40 patients with OHT were enrolled. CCT were measured by OCT3 and analyzed using ANOVA. The relationship of CCT and intraocular pressure (IOP) measured by Goldmann applanation tonometry were analyzed by linear regression. The inter-observer and intra-observer agreement of CCT measurement by OCT were analyzed by interclass correlation coefficient (ICC). The average CCT of normal subjects, patients with POAG, NTG and OHT were (525.31 +/- 32.18) microm, (531.87 +/- 31.58) microm, (507.61 +/- 21.56) microm and (574.09 +/- 27.84) microm, respectively. There was no significant difference between normal subjects and patients with POAG (P = 0.099). The average CCT of OHT patients was larger than those of other groups (P < 0.001). The average CCT of patients with NTG was less than those of other groups (P < 0.001). There was positive relationship between CCT and IOP in normal subjects (r = 0.318, R2 = 0.101, P < 0.001). The ICC of inter-observer and intra-observer agreement of CCT measurement by OCT were 0.995 and 0.996 respectively. Central corneal thickness could be measured by OCT accurately. The average CCT in the patients with NTG was thinner, but the average CCT in the patients with OHT was thicker than that of normal subjects. CCT could affect IOP measurement in the application of Goldmann applanation tonometry but with little significant.