Abstract
Abstract: :
Purpose: To determine if regional measures of optic disc surface topography can predict the progression of glaucomatous visual field defects. Methods: A retrospective analysis of optic disc surface topography (Heidelberg Retinal Tomograph, HRT) in patients with primary open angle glaucoma (n = 26). Patients were sub–grouped according to whether they exhibited progression (group P, n = 13) or non–progression (group NP, n = 13) of their visual field defects during the course of follow–up (mean follow–up = 3.2 years). Individuals in the P and NP sub–groups were matched for age (P group mean age = 73.6, NP group mean age = 73.8) and the extent of their visual field defect at the time of the baseline HRT examination. Optic disc topography was measured at 136 equally spaced (100 microns) locations along eight meridians within a circular region (radius = 1700 microns) centered on the optic disc. Changes to optic disc topography between baseline and follow–up were determined for each location and differences between the P and NP groups were analyzed using both cluster analysis and forward stepwise logistic regression. Results: No significant between–group differences in optic disc surface topography were evident for any of the locations except in a region along the superior and superior–nasal meridians at 300–400 microns from the center of the optic disc. In this region the surface height reduction tended to be greater in the P group than in the NP group. Cluster analysis confirmed a regional specificity for significant and near significant differences in the superior and superior–nasal regions 300–400 microns from the center of the optic disc. The forward stepwise logistic regression revealed a statistically significant (p < 0.05) between–group difference at 300–400 microns along the superior meridian. Conclusions: These findings strongly suggest that changes in the surface topography of regions of the superior optic disc inside the neuroretinal rim may be particularly sensitive indicators of progression of visual field defects in glaucoma patients.
Keywords: imaging/image analysis: clinical • visual fields • topography