Examining the Visual Impairment/Cognitive Impairment Co-morbidity

Title Examining the Visual Impairment/Cognitive Impairment Co-morbidity
Author, Co-Author Caitlin Murphy, David Nguyen-Tri, Robert Koenekoop, Olga Overbury
Topic Low Vision
Program Number
Ballroom A-B

Purpose: The number of seniors affected by Age-related Macular Degeneration (AMD) and early cognitive changes is on the rise. Recent studies have shown a high co-occurrence of these conditions. This, along with shared risk factors and similar histopathology suggests they may share genetic risk factors as well. The goal of this study is to explore the relationship among genotype, retinal structure and visual and cognitive function in this co-morbidity.

Method: Participants diagnosed with AMD were genotyped using a panel of AMD single nucleotide polymorphisms (SNPs). Analysis was focused on the CFH Y402H and ARMS2 A69S SNPs due their association with drusen and evidence of their association with cognitive impairment. Visual function was measured using traditional optometric tests including fundus photography. Optical coherence tomography/scanning laser ophthalmoscopy (OCT/SLO) was used to assess retinal structure and fixation stability. Cognitive function was tested using the Mini Mental State Exam (MMSE) and the Montreal Cognitive Assessment (MoCA).

Results: Of the 19 participants to date, ten carried the ARMS2 SNP and eight carried the CFH SNP. Six participants scored positive for mild cognitive impairment (MCI) on the MoCA. Preliminary results show that carriers of the CFH SNP have more retinal damage, but perform better cognitively compared to ARMS2 SNP carriers who show the opposite. The SNP in FADS1 (rs174547) that was part of the original panel but not the analysis was found in 15 of the 19 participants.

Conclusion: To date, this study agrees with others showing a co-occurrence of AMD and MCI. The CFH SNP did not occur as often as expected considering it is known to contribute to 50% of AMD cases. The FADS1 SNP, not intended to be part of this study, will be included in future analyses to explore the possibility of a Founder’s Effect. Further data collection and analysis is required to gain a better understanding of this co-morbidity.

Affiliation of Co-Authors School of Optometry, Université de Montréal, McGill Ocular Genetics Laboratory, McGill University, School of Optometry, Université de Montréal