# Glaucoma: What It Is, How It Is Detected, and What Happens Next URL: https://mohamedmohyudin.co.uk/eye-health/glaucoma-symptoms-diagnosis/ Last updated: 2026-09-08 Original clinical review: 2026-08-13; later editorial additions are source-based. ## Quick answer Glaucoma is a group of eye conditions in which the optic nerve is progressively damaged, usually linked to raised intraocular pressure. It is often painless and causes no early symptoms, so peripheral vision is lost gradually before patients notice. It is most commonly detected at a routine optician sight test through pressure, optic nerve and visual field checks. ## Key facts - Leading cause of irreversible blindness worldwide; around 700,000 affected in England - Usually painless with no early symptoms; peripheral vision lost gradually - Most commonly detected at a routine optician sight test - Key tests: tonometry, optic nerve assessment, visual fields, OCT, pachymetry - Treatment lowers eye pressure via drops, SLT laser or surgery - Free NHS sight tests for over-40s with a first-degree relative affected ## Introduction Glaucoma is the leading cause of irreversible blindness worldwide, affecting around 700,000 people in England alone. Its most insidious quality is that in most cases it causes no pain and no visual symptoms in the early stages — peripheral vision is lost gradually and the brain compensates so effectively that patients often do not notice until a substantial proportion of their visual field has gone. ## What is glaucoma? Glaucoma is a group of eye conditions characterised by progressive damage to the optic nerve — the cable of 1.2 million nerve fibres that transmits visual information from the eye to the brain. In most cases, this damage is related to raised intraocular pressure (IOP), though some patients develop glaucoma with IOP in the normal range (normal tension glaucoma). The most common type — chronic open-angle glaucoma (COAG) — develops slowly over years. Acute angle-closure glaucoma is a sudden, painful emergency (see our red eye article). Other types include normal tension glaucoma, pseudoexfoliative glaucoma, and pigment dispersion syndrome. ## Risk factors - Age — risk increases significantly after 60 - Family history — first-degree relative with glaucoma approximately doubles your risk - Elevated intraocular pressure - African-Caribbean ethnicity — higher prevalence and often earlier onset - High myopia (short-sightedness) - Long-term steroid use (eye drops, oral, or inhaled) - Diabetes and hypertension ## How is glaucoma detected? Glaucoma is most commonly detected at a routine optician visit. The key tests are: - Intraocular pressure measurement (tonometry) — a raised IOP is a risk factor but not diagnostic alone. - Optic nerve assessment — examination and photographs of the optic disc to look for characteristic changes (cupping, notching, haemorrhages). - Visual field test (perimetry) — a computerised test of the peripheral visual field. Loss of peripheral field is the hallmark of glaucoma damage. - OCT (optical coherence tomography) — high-resolution imaging of the retinal nerve fibre layer, detecting thinning before visual field loss occurs. - Pachymetry — corneal thickness measurement, as thin corneas give falsely low IOP readings. ## Treatment Glaucoma cannot be reversed — damage already done to the optic nerve is permanent. Treatment aims to lower IOP to prevent or slow further damage. - Eye drops — the first-line treatment. Prostaglandin analogues (latanoprost, bimatoprost) are most commonly used. Drops must be used every day, indefinitely. - Laser trabeculoplasty (SLT) — a laser procedure that improves drainage of fluid from the eye. Often recommended as a first-line treatment instead of drops. Effective in many patients for 3–5 years. - Surgery (trabeculectomy / tube implant) — for glaucoma not controlled by drops or laser. Creates a new drainage route for intraocular fluid. Highly effective but requires careful post-operative monitoring. ## NHS screening and optician referral In the UK, anyone over 40 with a first-degree relative (parent, sibling, child) with glaucoma is entitled to free NHS sight tests. If your optician suspects glaucoma, they will refer you to an NHS or private ophthalmology clinic for a comprehensive glaucoma assessment. ## Does Mr Mohyudin treat glaucoma in Yorkshire? He can examine the optic nerve, measure pressure, and explain the next step. He is not a glaucoma-only consultant. Ongoing drop changes, SLT, trabeculectomy and tube surgery are usually a glaucoma specialist’s or NHS glaucoma-service job. If a private cataract visit uncovers possible glaucoma, the honest outcome is a referral, not a premium lens sale. Use this page to understand the disease; use the NHS or a glaucoma clinic for long-term pressure care. ## When is glaucoma an emergency rather than a clinic booking? Acute angle-closure is a painful, red, misty-vision emergency with halos and nausea. That is eye casualty the same day (Huddersfield Royal Infirmary 01484 342000) or 999 — not a self-pay cataract or eyelid slot. Chronic open-angle glaucoma is the opposite: silent, slow, and found at the optician. Do not mix the two. ## Who should skip this practice for ongoing glaucoma care? Skip if you already have a glaucoma consultant and only need pressure checks and drop changes. Mr Mohyudin can examine the nerve, explain a referral, and operate on a cataract in a glaucomatous eye when that is the right sequence. Long-term pressure surgery is a glaucoma service job. Using a cataract visit to ‘sort the glaucoma’ with a premium lens is the wrong buy. ## Can cataract surgery help glaucoma? Removing a bulky lens can lower pressure a little in some eyes and is sometimes part of angle-closure management once the emergency is treated. It is not a substitute for drops or glaucoma surgery in open-angle disease. If both cataract and glaucoma are present, the teams should agree the order. That conversation is why mixed cases should not be booked from a lens advert. ## Why is a glaucoma plan based on more than one pressure reading? Ask the specialist how pressure measurements, the optic nerve assessment and visual-field results fit together. A single number does not describe the whole condition or show how quickly it is changing. Keep follow-up appointments even when the eyes feel comfortable: ongoing care is designed to detect changes that you may not notice yourself. Bring previous results if you move between providers. If drops, laser or another treatment are discussed, ask what the treatment is intended to achieve and how success will be monitored. Tell the team if putting in drops is difficult, if you miss doses or if side effects make the plan hard to follow. Do not stop prescribed treatment simply because your sight seems unchanged. Sudden severe eye pain with redness or vision changes needs urgent assessment. A routine cataract or general eye consultation should not interrupt established glaucoma follow-up. ## Questions to take to your appointment - What evidence supports the diagnosis and target pressure? - How will you tell whether the condition is stable? - Who should I contact if I cannot use the prescribed drops? ## Sources - [NHS: glaucoma](https://www.nhs.uk/conditions/glaucoma/) ## FAQs ### Can glaucoma be cured? Glaucoma cannot currently be cured, and damage already done to the optic nerve cannot be reversed. However, with early detection and consistent treatment to lower intraocular pressure, progression can be halted or slowed significantly, and most patients with glaucoma retain functional vision for life. ### My eye pressure was raised at the optician. Do I have glaucoma? Not necessarily. Raised IOP (ocular hypertension) is a risk factor for glaucoma but is not the same as a glaucoma diagnosis, which requires evidence of optic nerve damage or visual field loss. Around half of people with raised IOP never develop glaucoma. However, ocular hypertension does warrant monitoring and in higher-risk cases, treatment to lower pressure. ### Can I drive with glaucoma? It depends on the extent of visual field loss. DVLA regulations in the UK require drivers to meet minimum visual field and acuity standards. Patients with significant glaucoma should inform the DVLA and may be asked to undergo a formal driving visual field test. Your ophthalmologist can advise you on your specific situation. ### My optician said my pressures are ‘a bit high’. Should I go private tomorrow? Not usually. Ocular hypertension needs a proper glaucoma-style work-up — fields, OCT, discs — which the NHS glaucoma service or a glaucoma clinic does every day. Private speed helps if you cannot get that work-up; it does not mean you must pay for drops for life after one reading. ### Are free NHS sight tests enough to catch glaucoma? They are the main screening door in the UK, especially if you are over 40 with an affected first-degree relative. They are not a full hospital glaucoma assessment. Keep the optician appointments even if you also see a consultant.