Structure Function Correlation in Primary Open Angle Glaucoma

Glaucoma is an optic neuropathy characterised by progressive degeneration of retinal ganglion cells and axons that leads to nerve fibre loss, optic disc cupping, and consecutive glaucomatous visual field defects. It is considered to be one of the major causes of blindness worldwide. It is a well accepted fact least 25 - 40% of retinal ganglion cells need to be lost before statistically detectable visual field defects appear on automated visual field testing, which is also consistent with post-mortem histologic findings in glaucomatous eyes. Since the damage associated with glaucoma is irreversible, and retinal nerve fibre layer loss is considered as an early sign of glaucomatous damage, its early detection and prevention is warranted. Retinal nerve fibre layer studies can be undertaken through non - invasive, reproducible technologies such as optical coherence tomography, scanning laser polarimetry etc. The purpose of the study is to evaluate the relationship between visual fields and retinal nerve fibre layer thickness as measured by Cirrus spectral domain optical coherence tomography with visual fields by Humphrey Field Analyser (HFA) in early and moderate primary open - angle glaucoma.