Relationship of central corneal thickness with optic disc parameters: The Singapore Malay eye study

PURPOSE. To examine the relationship of central corneal thickness (CCT) with optic disc parameters measured by confocal scanning laser ophthalmoloscopy in a Malay population. METHODS. This was a population-based cross-sectional study of Asian Malay adults aged 40-80 years living in Singapore. Participants had a standardized interview, examination, and imaging at a study clinic. CCT was measured with an ultrasound pachymeter. Confocal scanning laser imaging was performed on all participants to obtain optic disc parameters. Multivariate regression analyses controlling for age, sex, intraocular pressure, and other potentially confounding factors were conducted separately for disc area, rim area, cup-to-disc ratio, and mean cup depth. RESULTS. Of the 3280 participants in the study, 2525 (77.0%) right eyes with reliable confocal scanning laser tomography images were included in this analysis, with 48 eyes defined to have primary open-angle glaucoma (POAG). In POAG subjects, CCT was positively correlated with rim area (regression coefficient of 0.372 mm ² per 100 μm CCT increase; P = 0.035) and negatively correlated with cup-to-disc area ratio (-0.160 per 100 μm CCT increase; P = 0.024). There was no relationship between CCT and disc size (P = 0.088). In the 2468 subjects without glaucoma, there were no associations between CCT and confocal scanning laser tomography parameters. CONCLUSIONS. In this population-based study, decreased CCT was associated with lower rim area and greater cup-to-disc area in subjects with POAG, but not in subjects without glaucoma.