The Relationship Between MRI-Measured Structure of the Visual Cortex and Visual Function in Patients With Glaucoma.

Abstract

Prcis: The area corresponding to the peripheral visual field in the primary visual cortex of the brain is associated with ophthalmologic parameters.

Purpose: Reproducing the relationship of the visual field with the primary visual cortex is known as retinotopic mapping. The primary visual cortex is known to be atrophic in glaucoma patients. However, there are few reports on which areas most reflect glaucomatous changes. In this study, we used magnetic resonance imaging to evaluate the relationship between various ophthalmic parameters and overall and regional structural changes in the primary visual cortex to better understand changes in the brain associated with glaucoma.

Materials and methods: Twelve healthy subjects [56.1±9.3 y old, male to female ratio 6:6, mean deviation (MD) 0.6±0.7 dB] and 23 patients with glaucoma (57.8±8.0 y old, male to female ratio 8:15, MD: -10.2±6.4 dB) were enrolled. We acquired 3D-T1-weighed images to measure the overall and regional gray matter density of the visual cortex based on a priori retinotopic projection. Optical coherence tomography and visual field testing were performed, and a weighted count of retinal ganglion cells (wRGC) was calculated from the ophthalmological tests. The Spearman rank correlation coefficient was used for evaluating the correlations between these structural parameters of the visual cortex and the ophthalmological parameters.

Results: The overall primary visual cortex was positively correlated with MD ( r =0.40, P =0.02) and wRGC ( r =0.41, P =0.02). Regarding retinotopic projection, the inner area in the visual cortex, which corresponds to the peripheral visual field, was positively correlated with MD and wRGC.

Conclusion: The inner part of the primary visual cortex, which corresponds to the peripheral visual field, is closely correlated with ophthalmologic parameters commonly used for diagnosing and detecting the progression of glaucoma clinically. This suggests that evaluation of this area with MRI may be of clinical use in glaucoma assessment and monitoring.