Narrow Angle Glaucoma
What is the angle?
A narrow angle is an anatomical configuration in the eye that under certain conditions can result in high eye pressure. High eye pressure may lead to glaucoma. The diagnosis of narrow angles is not the same as a diagnosis of glaucoma. Only a small percentage of patients with narrow angles develop glaucoma and early diagnosis and treatment can prevent the development of angle closure glaucoma.
The angle of the eye is located at the junction between the iris (the colored part of the eye) and the cornea (the transparent surface of the eye). The ciliary body, a ring of tissue behind the iris, produces fluid called aqueous humor. This fluid is internal and separate from tears, which is produced by glands outside the eye. The aqueous flows over the lens, then through the pupil and drains internally from the eye via the trabecular meshwork at the angle. As long as aqueous is drained at roughly the same rate it is produced, the eye maintains a normal pressure. If aqueous cannot drain as quickly as it is made, the eye pressure will go up. This situation can occur if the angle becomes critically narrow.
What makes the angle narrow?
The lens grows throughout life, increasing in size by adding on onion-like rings of tissue. The lens is located behind the iris and it moves the iris forward as it grows. In some people, this gradual forward movement can slowly narrow or crowd the angle, and this is why narrow angles tend to be seen more commonly as we age. Some eyes are more predisposed to narrow angles than others. Narrow angles are more commonly found in people over the age of 40, females, far sighted or hyperopic patients, and in people of East Asian, African and Inuit descent.
How can I care for my narrow angles?
The best way to care for this eye condition is to schedule follow up appointments with your eye doctor and to monitor yourself for symptoms of angle closure.
Various factors may induce angle closure, including low lighting conditions, pain, emotional upset or fright. A number of systemic medications, including allergy and cold medications, antidepressants and anticholinergics, carry warnings against use by patients "with glaucoma". These warnings most often refer to narrow angles as these medications may precipitate angle closure in the predisposed eye.
When should I call for help?
Symptoms that the angle is closing intermittently include episodes of blurred vision, perhaps seeing halos around objects, a headache-like pain around the eye or brow and a red eye. These symptoms can resolve spontaneously, and they can occur periodically over days or weeks. In addition, if the angle closes and does not reopen spontaneously, you may experience nausea and vomiting. Call your eye doctor's office immediately if you are experiencing these symptoms.
Treatment for narrow angles
Not all narrow angles require immediate treatment and your ophthalmologist may decide that you should have periodic follow-up to determine when treatment is indicated. Treatment includes placement of a microscopic hole in the iris using a laser. This procedure is known as laser iridotomy. Once aqueous can flow through the laser opening, the angle can open, and the risk of elevated eye pressure and damage to the optic nerve is reduced.
Laser iridotomy is an office procedure. Although the actual procedure only takes 5-10 minutes, expect to be in the office for about 2 hours for an eye pressure check about 1 hour after the laser procedure. The potential risks of this procedure includes inflammation, rise in eye pressure, bleeding, blurred vision and rarely glare and visual distortion. There is no activity restriction after the procedure.