Abstract
Purpose: :
The development of Alzheimer’s disease and age related macular degeneration (AMD) share similar histopathology, vascular risk factors and genetic predisposition. In this pilot study we examined the prevalence of macular and peripheral pathologies in the retina in patients with Alzheimer’s dementia and compared these to non-demented controls.
Methods: :
Optos P200C AF ultra-wide angle laser scanning ophthalmoscope (200°) colour and autofluorescence (AF) images were taken to determine the phenotypic variation in the macula and the periphery in 56 Alzheimer’s dementia patient and 48 controls. The patients had different severity of cognitive impairment as judged by their mini mental state examination. Images were graded in 3 zones: macula, mid and far periphery and the distribution and prevalence of drusen, pigmentary changes, atrophy or choroidal neovascularisation (CNV) was recorded in four sectors within these zones. All had blood taken for genotyping for complement factor H (CFH).
Results: :
Most patients had to be imaged through dilated pupils to achieve gradable images, while most controls needed no dilation. All but one patient had gradable quality images both on colour and AF imaging. Of those with macular pathology, all but 4 had peripheral pathology such as drusen and retinal pigment epithelial changes (chi²=18.1; p<0.01). Only one control, but 3 patients had end stage AMD. No significant differences have been found between patients and carers in CFH genotype, but there is a trend towards a higher prevalence of the His402 variant of in relation to peripheral pathologies (p=0.13).
Conclusions: :
Optos P200C AF ultra-wide angle laser scanning ophthalmoscope has potential value when imaging people who may be poorly compliant with traditional ophthalmological examinations, such as patient with dementia, especially after dilation. The ultra-wide angel images revealed wide ranging pathologies in the periphery, especially in far periphery, in Alzheimer’s disease patients. The extent of peripheral pathology and the potential association with CFH genotype warrant further investigation to better understand the association between genotype and phenotype in relation to Alzheimer’s disease and AMD.
Keywords: age-related macular degeneration • clinical research methodology • imaging/image analysis: clinical