Glaucoma
NICE NG81 — eye pressure, optic nerve damage and stepwise pharmacological management
Glaucoma is a group of eye conditions characterised by progressive optic nerve damage, leading to irreversible loss of vision. It is the second most common cause of blindness worldwide and affects around 700,000 people in the UK, with many more undiagnosed. Primary open-angle glaucoma — the most common form — is typically painless and asymptomatic until significant visual field loss has occurred, which is why regular eye examinations are critical for early detection. Raised intraocular pressure is the principal modifiable risk factor, and treatment aims to lower it sufficiently to halt disease progression.
Understanding Glaucoma
The eye continuously produces a fluid called aqueous humour, which normally drains out through a drainage angle between the iris and cornea. In primary open-angle glaucoma (POAG), the drainage angle remains open but the drainage system becomes less efficient over time, causing intraocular pressure to rise. In acute angle-closure glaucoma, the drainage angle becomes physically blocked — this is a medical emergency. Raised intraocular pressure (above around 21 mmHg) puts mechanical stress on the optic nerve at the back of the eye, gradually destroying nerve fibres. The resulting visual field loss starts peripherally and progresses inward. By the time central vision is affected, extensive and irreversible damage has occurred.
Who is at Risk and How is it Detected?
Risk factors for glaucoma include raised intraocular pressure (IOP), increasing age (over 60), a family history of glaucoma, Black or African-Caribbean ethnicity (higher prevalence and earlier onset), myopia (short-sightedness), and certain medical conditions such as diabetes and sleep apnoea. Optometrists screen for glaucoma during routine eye tests by measuring IOP, examining the optic disc, and assessing the visual field. Anyone with a parent or sibling diagnosed with glaucoma is entitled to free NHS eye tests. NICE NG81 recommends that people diagnosed with ocular hypertension or suspected glaucoma are referred to a hospital eye service or community glaucoma service for further assessment.
Treatment
The aim of treatment is to lower intraocular pressure to prevent or slow further optic nerve damage — it cannot restore vision already lost. Prostaglandin analogue eye drops (latanoprost, bimatoprost, travoprost) are the recommended first-line treatment in NICE NG81, as they are the most effective at lowering IOP and need only be applied once daily. Laser treatment — selective laser trabeculoplasty (SLT) — is now also recommended as a first-line alternative to drops and can provide IOP control without the need for daily medication. If drops or laser are insufficient, additional eye drops from other classes are added. Surgery (trabeculectomy) is reserved for cases where other treatments have failed. Regular monitoring of visual fields, IOP, and optic disc appearance is essential throughout treatment. This article has been prepared following careful evaluation of NICE NG81 (Glaucoma: Investigation, Treatment and Monitoring).