Abstract
Purpose:
Purpose Alzheimer’s disease (AD) is the most common form of dementia in the UK, and there are currently no curative treatments. Changes to peripapillary nerve fibre layer and optic nerve head have previously been identified on Optical Coherence Tomography (OCT) scans but no studies have utilised OCT to investigate foveal and parafoveal changes of individual retinal layers in AD. Our aim was to investigate changes in macular retinal layers using optical coherence tomography (OCT) with a view to investigate whether specific retinal changes occur in Alzheimer’s disease.
Methods:
17 participants with AD and 10 age-matched controls were recruited to the study. All participants were between 60-82 years and had particiapnts with AD were diagnosed within the last year.Scans were obtained in the macular region of the left and right eyes. The best scans were selected and the retinal layers were analysed using a custom written program which ran in imageJ software. Point measurements were obtained at the foveal pit and 1000 microns nasal and temporal to the foveal pit. The results were statistically analysed using linear mixed models.
Results:
Analysis of the macular layers showed that the nasal inner nuclear layer was significantly thinner in the patient group (p=<0.001).The central inner segment layer was also significantly thinner (p=0.03) in the patient group. Additionally, the retinal pigment epithelium layer was statistically thinner (p=0.02) nasally and temporally. The temporal retinal thickness (p=0.01) was significantly thinner which could be due to the thinning of temporal processing layers (p=0.03) in the patient group. No significant difference was noted in the retinal nerve fibre layer between the groups in our sample (p=0.40).
Conclusions:
This study has revealed novel changes in foveal and parafoveal retinal layers in patients with Alzheimer’s disease. No changes were noted in our sample in the parafoveal retinal nerve fibre layer in contrast to peripapillary retinal nerve fibre layer changes in AD as has been previously reported. Specific patterns of changes in the retinal layers identified by OCT could aid in the early diagnosis of Alzheimer’s disease possibly before clinical changes are apparent.
Keywords: 550 imaging/image analysis: clinical •
695 retinal degenerations: cell biology •
413 aging