Optic disk appearance in advanced age-related macular degeneration

Abstract

Purpose To describe and quantify the appearance of the optic disk in patients with advanced age-related macular degeneration (ARMD). Design Retrospective comparative study. Methods A total of 316 charts were reviewed. From these, 45 subjects with advanced ARMD (defined as geographic atrophy or disciform scar) in at least one eye were enrolled. Patients with glaucoma or glaucoma visual field defects were excluded. The probability of glaucomatous optic nerve damage was scored by evaluation of stereoscopic optic disk photographs in a masked fashion, according to a predefined evaluation scale and measured with confocal ophthalmoscopy (Heidelberg Retinal Tomograph; HRT). The area of macular involvement was measured in units of disk area. The optic disk evaluation scores and HRT measurements of a group of eyes with a large area of ARMD were compared with their fellow eyes with smaller areas of ARMD. The correlations between the area of macular involvement with the optic disk evaluation scores and HRT measurements were analyzed. Main outcome measures The optic disk evaluation scores and the HRT measurements between study groups. Results Eyes with larger areas of ARMD had optic disks that were more likely to be classified as glaucomatous by clinical evaluation (3.45 ± 0.23 vs 3.05 ± 0.18, P = .015) and by HRT imaging analysis (−0.995 ± 0.423 vs −0.376 ± 0.249, P = .030) than the fellow eyes with smaller areas of ARMD. For eyes with six or more disk areas of ARMD, larger areas of ARMD correlated with a higher cup/disk ratio ( P = .022), smaller neuroretinal rim area ( P = .022), and glaucomatous classification ( P = .040) with HRT discriminant function analysis. Conclusions Eyes with large areas of geographic or diskiform ARMD have optic disk structural alterations that resemble glaucomatous optic neuropathy. This should be taken into consideration when evaluating patients with ARMD for glaucomatous damage.