Glaucoma

Glaucoma is a group of optic neuropathies in which retinal ganglion cell axons are progressively lost, producing characteristic cupping of the optic disc and creeping peripheral visual field loss. In the common open-angle form the drainage angle looks normal but aqueous outflow is impaired, pressure rises, and damage accumulates over years without pain or noticeable symptoms. People typically do not notice field loss until a large proportion of nerve fibres are gone, and central vision is preserved until late — which is why glaucoma is a screening disease, detected on routine eye examination rather than by symptoms. Elevated intraocular pressure is the only modifiable risk factor with proven treatment benefit, and lowering it with prostaglandin analogues, laser trabeculoplasty or surgery reliably slows progression. Importantly, around a third of cases occur at statistically normal pressures, so a normal reading does not exclude glaucoma; disc appearance and field testing matter. Acute angle-closure glaucoma is a different entity entirely: sudden severe eye pain, a red eye, haloes around lights, nausea and blurred vision, and it is a same-day emergency. Supplement interest has centred on ginkgo and nicotinamide for neuroprotection; the data are early and do not replace pressure lowering.

• •No symptoms in early open-angle disease
• •Gradual loss of peripheral vision
• •Difficulty adapting to dim light
• •Bumping into objects on one side
• •Acute closure: severe eye pain, haloes, nausea, red eye

• •Raised intraocular pressure
• •Family history of glaucoma
• •Age over 60
• •African or Caribbean ancestry
• •High myopia or thin central cornea
• •Long-term corticosteroid use

Impaired aqueous outflow through the trabecular meshwork, raised intraocular pressure, poor optic nerve head perfusion, ageing, genetic predisposition, and structural factors such as thin corneas and high myopia.