Glaucoma
Normal-Tension Glaucoma
Also known as: NTG, normal tension glaucoma, low-tension glaucoma, low tension glaucoma
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
A subtype of primary open-angle glaucoma characterised by progressive glaucomatous optic neuropathy with corresponding visual-field loss and an open anterior chamber angle, despite untreated measured IOP remaining within the statistically normal range. Normal measured IOP alone does not establish NTG: reproducible structural-functional damage, progression where available, open-angle assessment and exclusion of non-glaucomatous optic neuropathy are required.
Recognition
Symptoms: what patients report
- Usually asymptomatic until field loss becomes functionally significant.
- Paracentral or fixation-threatening loss may cause reading difficulty, missed detail or other subtle central-field symptoms.
- Peripheral-field difficulty may emerge later; acuity can remain good despite clinically important loss.
Signs: what the examination shows
- Glaucomatous neuroretinal-rim thinning or focal notching with corresponding RNFL/GCC loss.
- Reproducible glaucomatous field loss, commonly paracentral, arcuate or nasal-step morphology; defects may be dense and close to fixation.
- Open anterior chamber angle on gonioscopy.
- Untreated measured IOP remains within the statistically normal range, recognising that isolated readings may miss diurnal peaks or underestimate pressure.
- Optic-disc haemorrhage may support progression-risk assessment but is not diagnostic of NTG.
- Thin central cornea may contribute to underestimation of measured IOP.
What OptoGuide™ covers for normal-tension 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
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.