Quantitative Evaluation of the Visual System in Glaucoma Patients

Millions of people in the world suffer from glaucoma, the second leading cause of vision loss in the world. Fewer than 50% of people with glaucoma are aware of their disease. The blindness caused by glaucoma is irreversible. Therefore, improved methods of screening and therapy for glaucoma are urgently needed.

Different imaging modalities exist for acquiring images of the eye. Most of these modalities focus on imaging the retina, but the human visual system does not only consist of the eye but it is extended into the brain through the optic nerve till the visual cortex. Figure 1 shows the human visual system.

Diffusion tensor imaging is based on diffusion weighted magnetic resonance imaging,  where the brwonian motion of water molecules is used to modulate the magnetic resonance signals. Therefore, diffusion weighted images can be used to probe the structure of the brain. The diffusion tensor imaging modality is the only modality that allows tracking the nerve fibers in the brain non-invasively. Figure 2 shows a color-coded fractional anisotropy image, that represents the diffusion tensor data in a brain slice.

The aim of this work is to identify the visual system on diffusion tensor images and analyze the abnormalities in it due to glaucoma. This facilitates the understanding of the pathophysiology of glaucoma.

The project consists of the following sub-projects:

• Automatic Segmentation of the Optic Radiation Using  DTI

• Analysis of the Optic Radiation in Glaucoma Patients