Acute Angle-Closure Glaucoma (cont.)
How Does a Health Care Provider Make a Diagnosis of Acute Angle-Closure Glaucoma?
During an examination for angle-closure glaucoma, an ophthalmologist performs the following tests: gonioscopy, tonometry, biomicroscopy, and ophthalmoscopy. Each test is described below.
- Gonioscopy is performed to examine the drainage angle of the eye; to do so, a special contact lens is placed on the patient's eye. This test is important to determine if the angles are open, narrowed, or closed and to rule out any other conditions that could cause elevated IOP. If the intraocular pressure is elevated and the angle is open, acute angle-closure glaucoma is not possible.
- Tonometry is a method used to measure the pressure inside the patient's eye. Eye pressure is measured in millimeters of mercury (mm Hg). Normal eye pressure ranges from 10 to 21 mm Hg. In a case of acute angle-closure glaucoma, IOP may be as high as 40 to 80 mm Hg.
- Biomicroscopy is a technique to examine the front of the patient's eyes and uses a special microscope called a slit lamp. This examination may reveal a poorly reactive pupil, a shallow anterior chamber, corneal swelling, redness of the white of the eye, and inflammation.
- Ophthalmoscopy is used to examine the patient's optic nerves for any damage or abnormalities; this may require dilation of the pupils to ensure an adequate examination of the optic nerves. If episodes of angle-closure glaucoma have been chronic (long term), this test may reveal excavation of the optic disk, which is a depression in the front surface of the optic nerve.
- Dilation of the pupils itself can cause acute angle-closure glaucoma in susceptible individuals.
If an attack persists or if several milder incidents of angle closure have occurred in the past, the ophthalmologist looks for signs of previous attacks.
- Peripheral anterior synechiae (scarring) and adhesions may be visible between the cornea and the iris. Peripheral anterior synechiae may destroy the trabecular meshwork.
- Prior attacks may cause a poorly reactive pupil because of damage to the muscle of the iris.
- Glaucoma flecks (also known as glaukomflecken) are spots on the lens of the eye. Glaucoma flecks may be seen if an acute attack of angle closure has occurred in the past.
- Atrophy of the iris provides further evidence of a prior attack if it occurred three or more weeks prior to the eye examination. The atrophied part of the iris appears gray, rather than blue, brown, or green.
Medically Reviewed by a Doctor on 9/11/2017
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