Despite age-related macular degeneration (AMD) being the commonest cause of blindness amongst the elderly in Western society, the incidence of new lesions is poorly documented and the natural history of existing disease remains ill understood.
Purpose: To document in an elderly population the incidence of new AMD lesions and the progression of pre-existing AMD over time.
Method: Baseline ophthalmic examinations were performed on a geographically defined random population sample of elderly people in 1982-4, and retinal photographs taken. The present study re-examined and re-photographed survivors after approximately 7 years using the same fundus camera. Photographs were randomly encoded, and independently graded for AMD features by two masked observers using the Wisconsin AMD grading system. Disagreements were resolved by review to reach a consensus.
Results: Eighty-two of the 88 participating survivors had photographs of gradable quality on both occasions in at least one eye. Mean age at follow-up was 87 years (range 84-97 years) and 70.7% of subjects were female. Paired photographs were available on 158 eyes, and showed important differences in drusen type, drusen area and characteristics of the retinal pigment epithelium (RPE) between initial and subsequent examinations. The 7 year incidence (and regression) of lesions was: drusen 30.6% (20.0%), RPE degeneration 54.5% (8.8%), increased pigment 11.6% (64.7%), subretinal haemorrhage 1.3%, subretinal scar/fibrin 1.3% and geographic study 1.3%.
Conclusion: These unique population-based results provide new insight into the natural history of AMD in an elderly population.