Definition:

Refractory glaucoma is defined as uncontrolled intraocular pressure with evidence of optic nerve and/or visual field deterioration despite maximally tolerated topical and/or systemic anti-glaucoma medications, failed surgical treatment or a combination of surgery and medicines.

Signs and Symptoms:

Open-angle glaucoma is painless and does not have acute attacks, thus the lack of clear symptoms make screening via regular eye check-ups important. The only signs are gradually progressive visual field loss, and optic nerve changes (increased cup-to-disc ratio on fundoscopic examination).

About 10% of people with closed angles present with acute angle closure characterized by sudden ocular pain, seeing halos around lights, red eye, very high intraocular pressure (>30 mmHg), nausea and vomiting, suddenly decreased vision, and a fixed, mid-dilated pupil. It is also associated with an oval pupil in some cases. Acute angle closure is an emergency.

Opaque specks may occur in the lens in glaucoma, known as glaukomflecken.

Causes:

Of the several causes for glaucoma, ocular hypertension (increased pressure within the eye) is the most important risk factor in most glaucomas, but in some populations, only 50% of people with primary open-angle glaucoma actually have elevated ocular pressure. Ocular hypertension—an intraocular pressure above the traditional threshold of 21 mm Hg or even above 24 mm Hg—is not necessarily a pathological condition but it increases the risk of developing glaucoma. One study found a conversion rate of 18% within 5 years, meaning less than 1 in 5 people with an elevated intraocular pressure will develop glaucomatous visual field loss over that period of time. It is a matter of debate whether every person with an elevated intraocular pressure should receive glaucoma therapy; currently most ophthalmologists favor treatment of people with additional risk factors.

Diagnosis:

Screening for glaucoma is usually performed as part of a standard eye examination performed by optometrists and ophthalmologists. Testing for glaucoma should include measurements of the intraocular pressure via tonometry, anterior chamber angle examination or gonioscopy, and examination of the optic nerve to look for any visible damage to it, or change in the cup-to-disc ratio and also rim appearance and vascular change. A formal visual field test should be performed. The retinal nerve fiber layer can be assessed with imaging techniques such as optical coherence tomography, scanning laser polarimetry, and/or scanning laser ophthalmoscopy (Heidelberg retinal tomogram). Visual field loss is the most specific sign of the condition; however, it occurs later in the condition.