Abstract
Purpose :
It has been suggested that the development of Alzheimer’s disease (AD) is associated with thinning of the peripapillary retinal nerve fiber layer (ppRNFL) due to ganglion cell loss and accumulation of drusen and that these reflect atrophy and plaque deposition in the brain, respectively. Here we report the results of baseline and progression characteristics of two prospective small studies that examined changes on ultra-widefield imaging (UWFI) and spectral-domain optical coherence tomography (OCT) to gain insights into retinal changes associated with AD.
Methods :
Color and autofluorescence UWFI and OCT images were acquired by Optos 200TX and Optos OCT SLO, respectively. In study 1 (S1), UWFI images of 72 healthy controls (HC) and 46 AD patients (Mini Mental Score Examination (MMSE) <20) were analysed for presence/absence and progression of drusen at baseline and at 2-year follow-up. In study 2 (S2), ppRNFL and peripapillary whole retinal (ppWR) thickness as well as macular volume (MV) and thickness (MT) were analysed at baseline and at 1-year follow-up (FU) on OCT images of 72 [4 FU] HC (MMSE>28), 23 [3 FU] typical AD (tAD) (MMSE<20) and 26 [5 FU] posterior cortical atrophy (PCA; MMSE<22) patients. The studies had full Ethical Committee approval. Statistical analysis was carried out using STATA and SPSS.
Results :
In S1, using UWFI we found that there is a significantly higher prevalence of hard drusen in the peipheral retina only in AD patients at baseline (p<0.05). Drusen numbers increased significantly in AD patients by the 2-year follow-up (p<0.05). In S2, using OCT, disease duration at baseline was not associated with any of the examined parameters (p>0.05 for all groups). However, the ppRNFL thickness measurements showed a significant age related decline (p<0.006). Importantly, UWFI and OCT imaging of the retina was quick and well tolerated in both studies. There were some difficulties with maintaining fixation or generating good quality images of patients with more advanced disease.
Conclusions :
These studies suggest that peripheral retinal hard drusen deposition is associated with AD, suggesting that UWFI might become a useful tool in monitoring progression in AD. The clinical utility of OCT on individual patient’s progression is yet to be determined.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.