Author: Claude (AI), from PubMed abstracts · Reviewed by: Dr Mina Abdelmseih · Reviewed: 2026-11-15 · Review due: 2027-11-15

Educational content only. Not personalised medical advice. Clinical decisions remain the responsibility of the treating clinician.

Primary Open-Angle Glaucoma: Diagnosis and Treatment Targets

Glaucoma is the leading cause of global irreversible blindness, with primary open-angle glaucoma (POAG) most prevalent in Africa [S3]. Lowering intraocular pressure (IOP) preserves the visual field, as shown by the first placebo-controlled trial [S4], and first-line selective laser trabeculoplasty (SLT) or, in advanced disease, primary trabeculectomy can outperform drops [S6] [S7] [S11].

Key points - Global glaucoma numbers were projected to rise to 111.8 million in 2040, disproportionately in Asia and Africa [S3]; POAG incidence is highest in low sociodemographic index regions and in Africa [S8]. - Latanoprost halved the risk of visual field deterioration over 24 months compared with placebo (HR 0.44) [S4]. - Prostaglandin analogues lowered IOP most among first-line drops, but within-class differences were small [S5]. - First-line SLT gave better long-term disease control than drops, with fewer trabeculectomies and cataract operations over 6 years [S6] and slower visual field loss [S11]. - In advanced glaucoma, primary trabeculectomy gave lower IOP and less field loss than drops at 5 years, with similar safety [S7].

Evidence last checked: 2026-10-17 (PubMed abstracts).

Red flags

• Optic disc haemorrhage: associated with progression of POAG (OR 4.51) and normal-tension glaucoma (OR 5.15) [S12].
• Rapid field loss: among ocular hypertensive eyes that developed field loss, 21% lost 1.0 dB per year or more and 5.4% lost 2.0 dB per year or more [S9].
• Advanced disease at diagnosis: medication was associated with more field progression than surgery in more severe glaucoma [S1] [S7].

Recognise it: who is at risk

• Risk factors for incident POAG: family history (OR 2.49), myopia (OR 2.08), elevated IOP (OR 1.13 per unit), older age and male sex [S8].
• People of African ancestry were more likely to have POAG than people of European ancestry (OR 2.80), and urban residents more than rural (OR 1.58) [S3].
• Incidence rises from 5.51 per 10 000 person-years at 40 to 44 years to 64.36 at 75 to 79 years [S8].
• Screening: the US Preventive Services Task Force found the evidence insufficient to assess the benefits and harms of screening asymptomatic adults in primary care (I statement) [S2]. This applies to a US primary care setting; high-prevalence settings may differ [S3] [S8].

Confirm it

• Diagnosis and monitoring in trials relied on visual fields, stereoscopic disc photographs, and disc imaging (HRT rim area, OCT nerve fibre layer) [S9] [S10].
• Visual field mean deviation deteriorated faster (-0.59 dB per year) than structural measures in UKGTS, partly explained by the structural floor effect [S10].
• Each mmHg of IOP accelerated functional and structural progression to a similar degree [S10].

Manage it: treatment and targets

Before acting on this section, check the national and local guidelines, product information and regulatory approvals that apply where you practise. See the medical disclaimer.

Tier A (primary care / no specialist)

• Refer people with a family history of glaucoma, suspicious discs or raised IOP to an eye service.
• Support adherence for patients already on drops; drop choice is a specialist decision. Dosing is not covered beyond the trial regimens below; follow local formularies.

Tier B (general eye clinic)

1. Start lowering IOP. In UKGTS, latanoprost 0.005% once daily to both eyes (as reported in [S4]) lowered IOP by 3.8 mmHg vs 0.9 mmHg with placebo at 24 months and prolonged visual field preservation [S4].
2. Choose a drug. In a network meta-analysis of 114 RCTs, 3-month IOP reduction was greatest with bimatoprost (5.61 mmHg), latanoprost (4.85) and travoprost (4.83), and smaller with timolol (3.70), brimonidine (3.59) and dorzolamide (2.49) [S5]. Adverse effects, patient preference and cost should guide choice [S5].
3. Offer SLT first where available. In LiGHT, 69.8% of SLT-treated eyes stayed at or below target IOP without further treatment at 6 years, progression was less frequent (19.6% vs 26.8%) and no serious laser-related adverse events occurred [S6]. The visual field rate was -0.26 vs -0.37 dB per year [S11].
4. Monitor the rate of field loss. Some ocular hypertensive patients lost vision rapidly despite trial follow-up, so high-risk patients need careful follow-up [S9]. Monitor more closely after a disc haemorrhage [S12].

Tier C (specialist centre)

• Advanced glaucoma at presentation. In TAGS, mitomycin C-augmented trabeculectomy gave mean IOP 12.07 vs 14.76 mmHg and better field mean deviation at 5 years, with similar quality of life and safety events (52.2% vs 57.9%) [S7].
• Earlier trials of initial surgery. A Cochrane review of 4 older trials (888 participants) found no significant difference in field progression in mild disease at 5 years, lower IOP but more eye symptoms with trabeculectomy, and more treatment failure with medication in the longer term; medications and surgery have changed since [S1].
• Treatment targets. Individual target IOP values are not specified in these abstracts; LiGHT used a protocol-defined target [S6].

Refer when

Pitfalls

• Equating a normal IOP reading with no glaucoma; disc haemorrhage predicts progression in normal-tension disease too [S12].
• Defaulting to drops when SLT is available and acceptable [S6] [S11].
• Starting drops alone in advanced disease without discussing surgery [S7].
• Judging stability on structure alone in advanced disease, given the floor effect [S10].

Evidence notes

• UKGTS was stopped early and its primary outcome changed after an interim analysis; it was funded partly by Pfizer [S4].
• LiGHT, TAGS and UKGTS were run in the UK [S4] [S6] [S7]; their applicability to African and Asian services is not tested in these abstracts.
• The disc haemorrhage evidence is observational [S12].
• Not covered by these sources: methods for setting target IOP, central corneal thickness, cost and drop availability in low-resource settings, and screening programmes outside the US.

Related articles

• Glaucoma Medications: Choices, Adherence and Side Effects
• Selective Laser Trabeculoplasty as First-Line Treatment
• Visual field testing and interpretation
• Optic disc assessment in glaucoma

References

See the numbered source list below. Each marker [S#] links to its PubMed and DOI record.