Abstract
Abstract: :
Purpose: To compare disk diameter (DD) measurements in glaucoma, glaucoma suspect, and normal disks using observer measurement methods. Methods: Population census based random sample of persons 50 years and older from the RES was used. We evaluated all available Nidek stereofundus photographs (1040). Structural criteria for definite open angle glaucoma (OAG) and suspected open angle glaucoma included two or more(definite) or one (suspect) of the following features: vertical or horizontal C/D ratio ≷0.7, C/D asymmetry ≷0.2, or presence of any focal neuroretinal rim changes. Right eye data were analyzed using SigmaStat. Horizontal (HDD) and vertical (VDD) disk diameters were determined in a masked manner by a glaucoma specialist (KFD) following the Beaver Dam Eye Study protocol. 1008 eyes (97%) were high enough quality to be used. Peripapillary atrophy (PPA) was also graded from 0 (none) to 4 (extensive). DDs were corrected for refractive error, but not for camera or stereoviewer magnification. Results: The number of disks classified as OAG, suspect, and normal were 48, 58, and 902 respectively. Using multiple linear regression we found age and refraction to be significant predictors for OAG. There were significant differences (P < 0.05) between the observer assessed VDD of normals (0.189 + 0.018in) and suspects (0.202 + 0.020in) as well as between the normals and the glaucoma group (0.206 + 0.029in). The HDD data showed the same pattern for analysis. PPA was significantly greater (p<0.05) in the glaucoma (1.52 + 0.99) and suspect group (1.26 + 1.00) vs normal (0.89 + 0.87). Conclusion: Observer measured optic nerves meeting structural criteria for glaucoma are significantly larger and have greater PPA than normal nerves.
Keywords: 354 clinical (human) or epidemiologic studies: prevalence/incidence • 498 optic disc