Abstract
Purpose :
Glaucoma is a neurodegenerative disease affecting both ocular and cerebral domains. However, it remains unclear if the brain changes are specific to glaucoma or are shared among optic neuropathies (ON). Here, we used the extensive UK Biobank (UKBB) datasets to examine the structural and functional brain changes in these patients.
Methods :
We used the UKBB to select participants aged 40 to 80 years old with brain magnetic resonance imaging (MRI) scans and excluded those with diabetes-related eye diseases, trauma-induced vision loss, other serious eye conditions, as well as extrapyramidal disorders, or degenerative, demyelinating, and inflammatory diseases of the nervous system.
Glaucoma subjects were included based on ICD-10 or self-reported glaucoma diagnosis. Non-glaucomatous ON included optic neuritis or optic atrophy, while excluding glaucoma diagnosis. Healthy subjects had no ICD-10 or self-reported glaucoma, or non-glaucomatous ON diagnosis.
We used greedy matching in R Studio to address age and gender biases, resulting in 1,229 glaucoma, 432 non-glaucomatous ON, and 18,550 healthy subjects. T1-weighted structural MRI, diffusion-weighted MRI, task-evoked functional MRI, physiometabolic, and ophthalmic datasets were then obtained from UKBB.
Results :
Both glaucoma and non-glaucomatous ON subjects exhibited thinner macular inner retinal layer (IRL) and reduced visual acuity (VA) compared to healthy subjects (Table 1). Glaucoma but not non-glaucomatous ON subjects also demonstrated lower diastolic blood pressure and lower platelet counts relative to healthy subjects.
In terms of brain changes (Table 2), glaucoma but not non-glaucomatous ON showed smaller lateral geniculate nuclei and visual cortex in lower-order (occipital pole) and higher-order (occipital fusiform, lateral occipital cortex) areas compared to healthy subjects. Furthermore, reduced fractional anisotropy was found in the posterior thalamic radiation of glaucoma subjects only. Task-based functional MRI also revealed significantly weaker face- and shape-related brain activation in glaucoma subjects only.
Conclusions :
While both glaucoma and non-glaucomatous ON had thinner macular IRL and reduced VA, glaucoma but not non-glaucomatous ON may also impact the volumes of the posterior visual pathway, optic radiation microstructures, and higher-order brain activity, along with physiometabolic changes.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.