Retinal changes may reflect dementia progression

VANCOUVER, British Columbia — Results of a cross-sectional prospective study showed that several retinal changes were associated with both posterior cortical atrophy and typical Alzheimer’s disease.

“Drusen deposition seems to be a good correlate between what happens in the brain and what happens in the retina, but there are different features that can distinguish between different disease types,” Imre Lengyel, PhD, said in his presentation at the Association for Research in Vision and Ophthalmology meeting.

The researchers took ultra-widefield color and autofluorescence images and OCT scans of 33 patients with posterior cortical atrophy (PCA), 28 patients with typical Alzheimer’s disease (tAD) and 71 healthy control subjects. They used the Optos P200Tx scanning laser ophthalmoscope and Optos OCT SLO.

They described PCA in the abstract as a neurodegenerative syndrome characterized by progressive degeneration of the parietal and occipital lobe with associated cortical visual impairment and said that its most common cause is AD.

Ultra-widefield imaging showed a lower prevalence of reticular pseudodrusen in PCA than in tAD, a lower prevalence of far-peripheral hyperfluorescence changes in tAD compared with PCA or healthy controls, and a more tortuous retinal vasculature in tAD compared with PCA or healthy controls. OCT showed a significant reduction in peripapillary outer plexiform-inner nuclear layer thickness in PCA compared with controls, the researchers reported in the abstract.

“There is a significantly higher proportion of [Alzheimer’s] patients diagnosed with hard drusen phenotype than controls, and PCA didn’t come up significantly different,” Lengyel said. “Drusen might still be an interesting factor to consider in monitoring Alzheimer’s disease in the eye.

“We found that subretinal deposits are more in superior area of the eye, but what was stunning, especially in typical AD but also in PCA, was that the prevalence of subretinal deposits is higher than in controls,” he said. “This is quite a new imaging marker in AD.”

Lengyel concluded: “Drusen deposition is associated with tAD and less with PCA, peripapillary pigmentary changes are associated with PCA but not tAD, subretinal deposits are more prevalent in both, vascular abnormalities are associated with tAD and possibly PCA, and we need well-characterized patients in a clinical setting.”

The researchers noted that the progression of dementia could be monitored through retinal changes in an inexpensive, well-tolerated and readily repeatable manner. – by Nancy Hemphill, ELS, FAAO

Reference:

Lengyel I, et al. Ultrawide-field retinal imaging markers for atypical and typical Alzheimer’s disease. Presented at: Association for Research in Vision and Ophthalmology; April 28-May 2, 2019; Vancouver, British Columbia.

Disclosures: Lengyel reports he is a consultant for and receives financial support from Optos. Please see the study abstract for all other authors’ relevant financial disclosures.