Macular function impairment in eyes with early age-related macular degeneration

Abstract

Purpose: To study different aspects of macular function in eyes with early age-related macular degeneration (early AMD: drusen with or without retinal pigment epithelium alterations) and normal visual acuity, to obtain a complete evaluation of macular function impairment in early AMD and to study the relationship between macular function and the ophthalmoscopic signs of early AMD.

Methods: Forty-seven subjects with early AMD and visual acuity better than 20/25 in at least one eye were studied: 34 patients had bilateral early AMD (group 1), 13 had neovascular AMD in the fellow (nonstudy) eye (group 2). Thirty-six age-matched healthy subjects were used as controls. Thirty degree stereoscopic fundus photographs and fluorescein angiography were performed to grade macular lesions. Macular recovery function, central visual field sensitivity, spatiotemporal contrast sensitivity, and the Farnsworth-Munsell 100 hue test were used to study different aspects of macular function.

Results: Except for color vision, all macular function tests were significantly impaired in eyes of patients with early AMD compared to those in control subjects. No functional difference was found between groups 1 and 2. The increase in drusen number negatively influenced macular recovery function. Increasing drusen confluence reduced macular recovery function as well as central visual field sensitivity and some selected spatial frequencies of spatiotemporal contrast sensitivity. Geographic atrophy of the retinal pigment epithelium and focal hyperpigmentation reduced macular recovery function and contrast sensitivity at the highest spatial frequency.

Conclusions: Macular recovery function central visual field sensitivity, and spatiotemporal contrast sensitivity are adequate and reliable indicators of macular function impairment in early AMD. Macular recovery function is the test that best reflects the ophthalmoscopic characteristics of early AMD because its deterioration parallels the worsening of typical fundus lesions. Function tests are valuable in the evaluation of patients with early AMD, particularly when interventional trials are planned.