Glaucoma-Specialist.com

Angle closure glaucoma  (H40.2)

Risk Factors
Major demographic risk factors for angle-closure are older age, female sex and Asian ancestry. AACG occurs in 1 of 1000 Caucasians, about 1 in 100 Asians, and as many as 2-4 of 100 Eskimos. Smaller anterior segment dimensions are the major ocular risk factor, with anterior chamber depth being strongly correlated with angle closure and angle-closure glaucoma.

Ocular risk factors include:
1. Narrower drainage angles
2. Shallower axial and limbal anterior chamber depth
3. Shorter axial length
4. Thicker lens
5. More anteriorly positioned lens
6. Smaller corneal diameter
7. Hypermetropic refraction

Gonioscopy remains the “reference standard” for diagnosing angle-closure, although imaging techniques such as UBM and anterior segment OCT may prove to be more reliable predictors of outcome than gonioscopy. Gonioscopy is an essential feature of the initial eye examination.

Treatment
Cataract surgery alone may be effective in angle closure glaucoma, depending on the degree of angle closure. Sometimes cataract surgery may be combined with trabeculectomy. Medical treatment is not recommended as a substitute for laser iridotomy or surgical iridectomy in patients with angle closure. Prostaglandin analogues appear to be the most effective medical agent in managing IOP control following laser iridotomy has opened an angle, regardless of the extent of synaechial closure.

The anterior segment OCT may be used as a method to detect occludable angles. The table below indicates the equivalent measurements on OCT that correspond with the gonioscopic findings. Therefore, an angle (TIA) of 15 degrees or less might be considered at risk of angle closure, and a TISA of less than 40 um ² might be considered an angle area narrow enough to warrant further intervention. Clinically, the decision on this depends on the overall clinical picture, including the clinical history gonioscopic appearances, and slit lamp biomicroscopy.

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