Your patient has high pressure

The key to managing these patients is to be able to differentiate angle-closure glaucoma from chronic open-angle glaucoma.

If the patient has angle-closure glaucoma, they are usually symptomatic with a red eye, pain, nausea, a cloudy cornea, a mid-dilated fixed pupil and pressure usually in excess of 40mmHg. The optometrist will usually document a shallow anterior chamber or narrow angles and should have measured the pressure. Feel the eyes – if the pressure is markedly raised, the affected eye will feel like a cricket ball; compare it to the other eye or to your own. Sometimes the episode of angle closure will have been precipitated by instillation of dilating drops. Such patients should be referred immediately to hospital as an emergency.

If the patient has open-angle glaucoma, the pressure is usually in the region of 24mmHg to 32mmHg. The optician will have commented on the optic disc, and if there is a significant cup associated with the raised pressure, the patient probably has glaucoma. The eye is comfortable and the patient is usually asymptomatic. There may or may not be a visual field defect. Raised intraocular pressure causes damage over several months and so the urgency of referral is minimal. Such patients do require referral to the hospital eye services, but they can be referred through the usual channels. If the pressure is closer to 40mmHg and the optic disc is described as markedly cupped, then an urgent referral via letter is warranted, as here the progression of glaucoma can be quite quick. The sooner the patient is seen and started on treatment, the better.