Relationship between central corneal thickness and severity of glaucomatous visual field loss in a primary care population

Abstract

Background Although the ability of central corneal thickness (CCT) to predict development of primary open-angle glaucoma has become increasingly well recognized, the ability of CCT to predict severity of glaucoma remains uncertain. This study was designed to expand the available knowledge about the relationship between CCT and glaucoma severity. Methods Retrospective identification of all patients with a clinical diagnosis of either primary open angle glaucoma (POAG) or ocular hypertension who were seen from September 2002 through May 2003 at the Albuquerque VA Medical Center eye clinic was completed. Eligible subjects were segregated into no, mild, moderate, or advanced visual field loss groups based on Advanced Glaucoma Intervention Study (AGIS) visual field scoring criteria. Following statistical analyses comparing the visual field groups, the sample was divided into thin, intermediate, and thick CCT groups, and further analysis was performed. Results Mean CCT was significantly higher in the no field loss group compared with all 3 groups with glaucomatous visual field loss. Mean CCT was not statistically different, however, between the mild, moderate, and advanced visual field loss groups. In linear regression analyses, no significant relationship was found between CCT and severity of visual field loss. Conclusions Although CCT was associated strongly with development of POAG-related visual field loss, CCT was not associated with severity of visual field loss in this study. These findings suggest that glaucoma patients with thinner corneas are just as likely to have advanced levels of field loss as glaucoma patients with thicker corneas. Prospective studies are needed to validate these findings.