Related Experiment Video
Updated: Jul 17, 2026
07:11
Functional Magnetic Resonance Imaging (fMRI) of the Visual Cortex with Wide-View Retinotopic Stimulation
Published on: December 8, 2023
Retinotopic organization of primary visual cortex in glaucoma: a method for comparing cortical function with damage
Robert O Duncan1, Pamela A Sample, Robert N Weinreb
1Hamilton Glaucoma Center, Department of Ophthalmology, University of California, San Diego, California 92093, USA. rduncan@eyecenter.ucsd.edu
Investigative Ophthalmology & Visual Science
|January 26, 2007
Summary
Functional magnetic resonance imaging (fMRI) can measure changes in the visual cortex related to optic disc damage in primary open-angle glaucoma (POAG). This novel method links brain activity to glaucoma-induced neurodegeneration.
Area of Science:
- Neuroscience
- Ophthalmology
- Medical Imaging
Background:
- Primary open-angle glaucoma (POAG) is a leading cause of irreversible blindness.
- Optic disc damage in POAG leads to progressive vision loss.
- Understanding the cortical consequences of optic disc damage is crucial for patient management.
Purpose of the Study:
- To establish a novel method for quantifying the relationship between primary visual cortex (V1) functional organization and optic disc damage in POAG.
- To project scotomas onto a flattened cortical representation to measure these changes.
Main Methods:
- Functional magnetic resonance imaging (fMRI) was employed in six POAG subjects.
- Optic disc and retinal nerve fiber layer (RNFL) damage were assessed using scanning laser polarimetry (GDx), confocal scanning laser ophthalmoscopy (HRT), and optical coherence tomography (OCT).
- Cortical activity was compared between glaucomatous and fellow eyes during visual stimulation, correlating fMRI responses with RNFL thickness and optic disc measurements.
Main Results:
- fMRI responses in V1 showed a significant correlation with measurements of optic disc damage.
- Correlations between fMRI and OCT (RNFL), HRT (mean height contour), and GDx (RNFL) were r = 0.90 (P = 0.02), r = 0.84 (P = 0.04), and r = 0.79 (P = 0.063), respectively.
- The observed correlations were statistically significant, with a low probability of occurring by chance (P = 0.0003).
Conclusions:
- Altered cortical activity in human V1 is consistent with optic disc damage in POAG patients.
- fMRI presents a potential non-invasive method for quantifying cortical neurodegeneration in POAG.
- This approach may aid in monitoring disease progression and treatment efficacy.
Related Concept Videos
01:20Anatomy of the Eyeball
The eye is a spherical, hollow structure composed of three tissue layers. The outer layer — the fibrous tunic, comprises the sclera — a white structure — and the cornea, which is transparent. The sclera encompasses some of the ocular surface, most of which is not visible. However, the 'white of the eye' is distinctively visible in humans compared to other species. The cornea, a clear covering at the front of the eye, enables light penetration. The eye's middle layer, the vascular tunic,...
01:24Vision
Vision is the result of light being detected and transduced into neural signals by the retina of the eye. This information is then further analyzed and interpreted by the brain. First, light enters the front of the eye and is focused by the cornea and lens onto the retina—a thin sheet of neural tissue lining the back of the eye. Because of refraction through the convex lens of the eye, images are projected onto the retina upside-down and reversed.
01:25Glaucoma: Overview
Glaucoma is an eye condition characterized by increased intraocular pressure that damages the retina and optic nerve, leading to irreversible blindness if left untreated. The human eye has various components, including the cornea, iris, pupil, lens, and optic nerve. Aqueous humor is secreted by the epithelium of the ciliary body in the posterior chamber and flows through the trabecular meshwork and canal of Schlemm, maintaining normal intraocular pressure. The trabecular meshwork and the canal...