What investigations should be performed in primary care before referring a patient for suspected glaucoma?

Before referring a patient for suspected glaucoma in primary care, the following investigations should be performed:

• Central visual field assessment using standard automated perimetry (full threshold or supra-threshold).
• Optic nerve assessment and fundus examination using stereoscopic slit lamp biomicroscopy (with pupil dilatation if necessary), and optical coherence tomography (OCT) or optic nerve head imaging if available.
• Intraocular pressure (IOP) measurement using Goldmann-type applanation tonometry. Non-contact tonometry should not be used as the sole basis for referral decisions.
• Peripheral anterior chamber configuration and depth assessment using gonioscopy or, if gonioscopy is not available or the patient prefers, the van Herick test or OCT.

Repeat visual field assessment and IOP measurement on another occasion should be considered to confirm findings, unless urgent referral is clinically indicated.

Referral should be made if there is optic nerve head damage, a visual field defect consistent with glaucoma, or an IOP of 24 mmHg or more measured by Goldmann applanation tonometry.

All examination and test results should be provided with the referral.

Patients with IOP below 24 mmHg should continue regular visits to their primary eye care professional.

These investigations and referral criteria are based on NICE guideline NG81 on glaucoma diagnosis and management.