Macular thickness may be linked to dementia, a study in Ophthalmology reports.

The investigation included 975 Japanese patients approximately 73 years old who were given vision and mental health screenings. The vision exam included fundus photography, intraocular pressure measurements and refraction. Investigators used spectral-domain OCT to assess retinal nerve fiber layer thickness (RNFL), ganglion cell-inner plexiform layer, ganglion cell complex, full macular thickness and peripapillary RNFL.

Researchers also performed cognitive tests and then placed the participants into three groups: healthy control, mild cognitive impairment or dementia.

The study found significant differences in the three groups in all layers and ganglion cell complex thickness, but not in peripapillary RNFL thickness. After adjusting for age, sex, educational status and refraction, researchers reported full macular and ganglion cell complex thickness were inversely associated with the presence of dementia. However, they found no link between peripapillary RNFL thickness and dementia. Additionally, ganglion cell-inner plexiform layer, ganglion cell complex and full macular thicknesses were all associated with the presence of dementia in the inferior sectors.

The study’s results suggest that OCT measurements of the macula could be superior to those of peripapillary RNFL in assessing neurodegenerative changes and may be a potentially useful diagnostic biomarker of cognitive function, the researchers said.