Clinical and OCT Optic Nerve Head Parameters Associated With Glaucoma Severity
Purpose
Cup-to-disc (c/d) evaluation is the mainstay of clinical glaucoma management. However, recent work evaluating OCT data has suggested that other optic nerve head parameters may be superior in evaluating glaucoma. In this study we examine clinical and OCT optic nerve head parameters and their relationship with glaucoma severity.
Methods
A retrospective chart review was conducted of 144 eyes diagnosed with primary open angle glaucoma. Optical Coherence Tomography reports from a Zeiss Cirrus device were obtained for each patient, with several optic nerve head parameters recorded. Additionally, the EMR record was queried to obtain clinical exam information. Visual fields were reviewed and graded, and a univariate and multiple regression analysis was performed to determine which optic nerve head parameter was most associated with glaucoma severity.
Results
Of the parameters measured average RNFL, and rim area were the most highly correlated with glaucoma severity (r = -0.64, -0.62 respectively). This exceeded the correlation of both clinical as well as OCT vertical c/d (r = 0.47, 0.53). Disc area is poorly correlated with glaucoma severity (r = 0.01). Multiple regression analysis revealed 3 variables; RNFL, RNFL symmetry, and rim area, which added significantly to the prediction at the p < 0.05 level.
Conclusion
While c/d is the primary way of assessing glaucoma clinically, our data suggest that other optic nerve head parameters including RNFL, RNFL symmetry, and rim area may also be independent predictors of glaucoma severity.