Glaucoma
Primary Open-Angle Glaucoma
Also known as: POAG, primary open angle glaucoma, open angle glaucoma, chronic glaucoma, OAG, optic nerve cupping, glaucomatous visual field loss, elevated IOP
Filed as: Routine
Source-cited from the record's own evidence list. Clinical content programme led by Dr Ankit Mathur, PhD, Grad Cert Ocu Thera, B.S. Optom. How the clinical content is governed
Clinical decision support only
Overview
Chronic progressive optic neuropathy with characteristic disc and field changes and open angles. IOP is the main modifiable risk factor, but a pressure reading above the statistically normal range is not required: normal-tension glaucoma is the normal-IOP subtype of this open-angle disease spectrum. Diagnosis rests on repeatable, concordant structural and functional damage after considering mimics and pressure context. RANZCO collaborative-care model: ophthalmologist establishes diagnosis and management plan; optometrist monitoring is acceptable when stable and under agreed protocol. Ophthalmologist-led care mandatory for unstable, advanced, or newly diagnosed cases.
Recognition
Symptoms: what patients report
- Often asymptomatic until advanced — peripheral field loss goes unnoticed.
- Gradual peripheral field loss — may present as bumping into objects, difficulty in dim light.
- Central vision preserved until late — explains late presentation.
- No pain, no redness — distinguishes from angle closure.
Signs: what the examination shows
- Optic disc: enlarged cup, vertical elongation, rim thinning, notching, asymmetry between eyes.
- Retinal nerve fibre layer defects — slit, wedge, or diffuse.
- Visual field: arcuate scotoma, nasal step, paracentral defects, field loss correlating with disc.
- IOP: may be elevated, high-normal, or within the statistically normal range; the latter requires the normal-tension glaucoma pathway and review of prior treatment, CCT, diurnal variation, and secondary causes.
- Gonioscopy: open angles — essential to confirm open-angle diagnosis.
- Central corneal thickness — thin corneas may artefactually lower IOP readings.
What OptoGuide™ covers for primary open-angle glaucoma
- Pattern reasoning: what this combination of findings points to, and its differentiators
- Don't-miss risks and escalation triggers
- Management tiers with linked Australian therapeutics
- Referral urgency, specialty, and letter drafting
Sources
- Glaucoma (chronic open angle) POAG — College of Optometrists CMG
- Primary Open-Angle Glaucoma PPP — AAO
- Primary Open-Angle Glaucoma Preferred Practice Pattern®. Gedde SJ, Bowden EC, Challa P, et al. Ophthalmology. 2026;133(4):P1-P103.
- Structural and functional differentiation between compressive and glaucomatous optic neuropathy. Laowanapiban P, Sathianvichitr K, Chirapapaisan N. Scientific Reports. 2022;12(1):6795.
- Glaucoma in Adults—Screening, Diagnosis, and Management: A Review. Stein JD, Khawaja AP, Weizer JS. JAMA. 2021;325(2):164-174.
- Centre for Eye Health — Chair-side Reference: Glaucoma Medications for Optometrists
- Centre for Eye Health — Chair-side Reference: Structure-Function Relationship in Glaucoma
Standard texts: Kanski's Clinical Ophthalmology: A Systematic Approach, The Wills Eye Manual, Oxford Handbook of Ophthalmology, Oxford American Handbook of Ophthalmology, Signs in Ophthalmology: Causes & Differential Diagnosis.