Glaucoma: an eye or a brain disease?

Although glaucoma is traditionally considered an eye disease, numerous MRI studies have shown that the visual system of the brain is affected as well. This involvement could be explained by decreased visual input, but could also indicate that glaucoma has a brain component. I addressed this outstanding question by investigating brain scans of patients with glaucoma (European and Japanese), subjects with monocular blindness and healthy controls. I found that glaucoma — and not monocular blindness — is associated with white matter changes in the visual system. These findings suggest that decreased visual input alone cannot cause these changes. In addition, I investigated brain structures beyond the visual system. I found that both glaucoma and monocular blindness are associated with white matter changes in vision-related and non-vision brain structures. However, those in glaucoma are more extensive (e.g. more affected structures). In my view, these findings indicate the contribution of an independent brain component to glaucoma. This thesis contributes to the idea that neuroprotective medication could be prescribed to prevent degeneration of the visual pathways and other brain structures, in addition to the standard treatment that is aimed at the eye. Furthermore, the involvement of the brain suggests that neuroimaging - over time – will be required in the clinical evaluation of disease progress and treatment outcome. My recommendation for future research is to start developing MRI-based tools that are able to evaluate and monitor disease progression and the effect of neuroprotection beyond the eye at an individual level.