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.