Modeling the patterns of visual field loss in glaucoma

Area of Science:

• Ophthalmology
• Computational Neuroscience
• Medical Imaging

Background:

• Glaucoma is a leading cause of irreversible blindness.
• Characterized by progressive optic neuropathy and characteristic visual field defects.
• The precise mechanism of glaucomatous visual field loss remains under investigation.

Purpose of the Study:

• To develop a computer model simulating neural loss in the anterior visual pathways.
• To test the hypothesis that diffuse neural loss can cause glaucoma-like visual field patterns.
• To investigate the role of optic nerve head (ONH) fiber damage patterns in glaucoma.

Main Methods:

• Modeled retinal ganglion cells and their axons to the ONH.
• Incorporated differential axon resistance to stress based on ONH location and vascularization.
• Simulated two damage patterns: diffuse (random fiber removal) and ordered (anteroposterior elimination).
• Extracted and analyzed visual field defects at various damage stages.

Main Results:

• Random fiber loss did not replicate the characteristic glaucomatous pattern loss.
• Ordered, anteroposterior fiber elimination produced a radial pattern, enhanced by vessel protection.
• Scotomas were detected earlier in peripheral visual fields due to increasing receptive field size with eccentricity.

Conclusions:

• Glaucomatous pattern loss cannot be solely attributed to random neural fiber loss.
• Anteroposterior ONH damage, particularly with central vessel protection, can explain the radial progression of scotomas in glaucoma.