Abstract
Purpose: :
Wet macular degeneration is broadly cited as the real problem of AMD, often with reference to Ferris, Fine and Hyman’s 1984 study finding 10% of wet AMD responsible for 90% of the legal blindness caused by AMD, and the vast majority of clinical and research attention has focused on wet AMD. The observation of many in vision rehabilitation, however, is that dry AMD is at least as big a problem as wet. This may be in part because of treatments for wet since 1984 (even prior to anti-VEGFs) and it is definitely in part because legal blindness is not an index of functional deficit. This study was undertaken to elucidate the relative impact of dry vs wet AMD on vision, function, and lives.
Methods: :
Retrospective chart review of new patients with AMD presenting to the Henry Ford Visual Rehabilitation and Research Center between 1999 and 2003. Exclusion criteria were ophthalmological comorbidities or physical or cognitive comorbidities causing additional functional deficits. Chart review included visual acuity, contrast sensitivity, scotoma and PRL parameters, depression score, functional complaints, hours of rehabilitation required and referral source. Fisher’s exact tests were used for all variable categories except visual acuity measures for which Kruskal-Wallis tests were applied.
Results: :
Among 467 subjects, 207 had wet AMD (44.2%), 260 dry (55.7%); wet 38% male, 61% female; dry 25% male, 74% female (p=0.0166). Statistically significant differences were found in visual acuities, with wet responsible for 59.3% and dry 40.7% of the legal blindness. Severe contrast sensitivity loss was found in 54.1% with wet and was 42.3% with dry (marginally significant p=0.0556). Difficulty reading cited by 99.5% with wet and 98.8% with dry. Rehabilitation training was required by 79% with wet, 73% with dry: 27% with wet and 17% with dry required 7 to 9 hours of training and 45% with wet and 51% with dry required 1 to 6 hours. (p=0.0026). Geriatric Depression Scale scores suggesting depression/ probable depression were similar: wet 29%, dry 26%.
Conclusions: :
Slightly more patients had dry than wet AMD. Wet was responsible for more legal blindness than dry, although less than previously reported: 59.3% to 40.7% vs 90% to 10%. Almost 100% of both groups had difficulty reading and similar numbers in each group required rehabilitation training, though fewer hours were required for dry than wet. Our results suggest that both wet and dry AMD significantly impact function and quality of life and that the patients’ experiences of functioning with each are sufficiently similar that dry AMD deserves recognition as a real problem and equal attention by clinicians and researchers.
Keywords: age-related macular degeneration • low vision • aging: visual performance