Assessing Peripheral Retinal Drusen Progression in Alzheimera??s Dementia: A Pilot Study Using Ultra-Wide Field Imaging

摘要

Purpose: The development of Alzheimera??s dementia (AD) and age-related macular degeneration (AMD) share many similarities including formation of extracellular deposit. Previously we reported an association between peripheral retinal drusen formation and AD. Cognitive function usually declines significantly in two years in AD. Therefore, the purpose of this study was to investigate whether there are changes in peripheral drusen deposition at the 2 years follow-up of the same AD population. Methods: Colour images were taken by the OPTOMAP P200C AF ultra-wide field laser scanning ophthalmoscope to determine changes in drusen prevalence and distribution in 14 AD patients and 15 controls. For grading purposes, the periphery was divided into two zones (zone 4 and 5) to extend the standard macular grid (Zone 1-3). Detailed progression data were collected by manually drawing drusen and their distribution on pairs of baseline and follow up images. Results: All AD patients and no controls required pharmacological dilation for imaging. There was no significant age difference between AD patients and controls (77.7?±7.2 vs. 71.3?±10.2; p0.1). AD status was confirmed by application of NINCDS-ADRDA criteria (MMSE scores raged between 14 and 26). On grading for drusen, both patients and controls progressed in two years. However, progression in patients was more prevalent than controls in all zones (Zone1-3: 19.2% vs 3.3%; Zone 4: 17.2% vs 8.3% ; Zone 5: 12.0% vs 4.2%). In addition there were many more ungradeable areas in AD patients in Zone 4 and 5 (12.0% vs 5.4% and 18.3% vs 29.3% respectively). Qualitative analysis of the number and the area covered by drusen showed larger coverage in patients both at baseline and especially at follow-up. Conclusions: Ultra-wide field imaging revealed significant progression in drusen deposition in AD within two years. Together with the earlier reported significant association between AD and peripheral hard drusen phenotype, these findings suggest that monitoring for the development and progression of pathological changes in the peripheral retina might serve as a valuable tool in detecting and monitoring the progression of AD. Further work is required to develop the understanding of these associations which may lead to peripheral drusen acting as a surrogate marker for plaque development in the central nervous system.