Ganglion cell-inner plexiform layer (GC-IPL) thickness may be associated with an increased risk of dementia, according to a study published in Ophthalmology Science.
Researchers conducted a study of 1078 participants (mean age 74±6.5 years, 637 women) to assess potential associations between dementia and GC-IPL and retinal nerve fiber layer (RNFL) thicknesses. They performed complete ophthalmic exams with dilation, obtained swept-source optical coherence tomography (SS-OCT) images, and administered a Mini-Mental State Examination (MMSE) to all participants to obtain retinal parameters and assess cognition. The team administered additional cognitive functioning tests to patients who failed to meet the passing criteria for the MMSE.
Investigators determined that 61 participants had dementia. They found that thinner GC-IPL thickness correlated with an increased likelihood of dementia after adjusting for potential confounders (OR=1.62 [95% CI, 1.30-2.01] per 1 standard deviation decrease in GC-IPL thickness, P <.001). However, they observed no significant association between the likelihood of dementia and RNFL (P =.10).
The researchers also noted that GC-IPL thickness was associated with lower volume in areas of the brain linked with both cognition (hippocampus, amygdala, and entorhinal area) and vision (lingual gyrus, cuneus, and thalamus).
“The present data revealed that lower GC-IPL thickness was significantly associated with a higher likelihood of the presence of dementia and lower volumes of several brain regions related to cognitive or visual function,” according to the investigators. “Our findings suggest that the measurement of GC-IPL thickness by an SS-OCT, which is a noninvasive, convenient, and reproducible device, might be a useful image marker for identifying high-risk individuals with dementia.”
Study limitations include a small sample size of patients with dementia, and possible geographic bias resulting from selecting participants from 1 local community.
Ueda E, Hirabayashi N, Ohara T, et al. Association of inner retinal thickness with prevalent dementia and brain atrophy in a general older population: the Hisayama Study. Ophthalmol Sci. Published online April 19, 2022. doi:10.1016/j.xops.2022.100157