Closed Angle (Acute) Glaucoma

Closed angle glaucoma, also known as acute glaucoma, is an eye disease which needs an emergency treatment. The number of people losing their eyesight due to this condition is on the rise. To know more about this eye disease, read on...

Closed angle glaucoma or acute glaucoma is one of the four types of eye diseases that come under glaucoma. It is found to be more common in people having hypermetropia(long sight). Glaucoma occurs mainly because of sudden elevation of the IOP (Intraocular Pressure-pressure in the eye).

In this condition, the IOP increases suddenly because the flow of the fluid, aqueous humor that drains out of eye, is blocked. With advancing age the chances of being affected by closed angle glaucoma increase.

The aqueous humor present in the eye is produced by ciliary processes; it then flows from the posterior chamber of the eye to the anterior chamber through the pupil.

The humor flows out of the eye through the trabecular meshwork at an angle of the eye. Trabecular meshwork is present near the iris. It is made up of lose fibers and it filters the aqueous humor as it flows out of the eye.

Now, in acute glaucoma, this flow of the humor is blocked. The iris is either pulled or pushed against the trabecular meshwork at an angle of the anterior chamber of the eye.

Due to this pull or push of the iris, the angle gets closed. The closure of the angle results in storage of humor in the eye and this prevents it from draining out. The blockage of the flow of humor finally results in an increase in the IOP.

People having hypermetropia are more susceptible to acute glaucoma, since their anterior chambers are shallow and angles narrow. As we grow old, the lens of the eye grows, thereby pushing the iris forward, and thus increasing the chance of being affected by acute glaucoma.

Late Dr. Ronald Lowe analyzed some factors that may act as catalysts in causing acute glaucoma. The most significant factor is illness (like cold/influenza). Accidental damage to the eye, mental imbalance, and side effects of eye drops, are some other factors.

In acute glaucoma, since the rise in IOP is sudden, the symptoms can also be sudden and dramatic at times.

• Blurring of vision and/or seeing haloes
• Red eye
• Nausea and vomiting
• Headache
• Eye pain

It is possible that some people experience intermittent attacks of angle closure, where the angle does not get closed completely. This is known as subacute glaucoma. People suffering from subacute glaucoma may not experience the above mentioned symptoms, but may have slight eye pain, blurred vision and/or may see haloes. Subacute glaucoma gets cured when the angle reopens.

One should consult an ophthalmologist as soon as possible if any symptoms of acute glaucoma are observed. Following are some of the tests involved in diagnosing this disease.

• Tonometry: This test measures the eye pressure. Eye pressure is measured in mm Hg. 10-21 mm Hg is the normal eye pressure range. In case of closed angle glaucoma, it can be 40-80mm Hg.

• Biomicroscopy: This test uses a special microscope to test the eye. The test may reveal problems like redness around the iris, narrow anterior chamber angle, poorly reacting pupil, etc.
• Ophthalmoscopy: This test is used to check whether the optic nerves are damaged.

• Gonioscopy: This test analyzes the angle of the eye. This helps in determining whether the drainage angle is open, closed or narrowed.

In case the patient has experienced a couple of intermittent attacks before, then the ophthalmologist confirms the occurrence of the attack with the help of following signs.

• Glaucoma flecks: These are seen on the eye lens if an attack has occurred in the past.
• Atrophy: The atrophied area of the iris is gray in color in case of a prior attack.

Closed angle glaucoma needs an emergency treatment, as it may lead to blindness if not treated immediately. Medicines in the form of drops/pills are used to reduce the IOP. Iridotomy is the operation carried out in emergency cases.

In iridotomy, a new channel is formed to help the humor flow out of the eye. Iridotomy involves the use of LASER. The formation of this new channel prevents further attacks.

• The occurrence of closed angle glaucoma is also influenced by the race to which a person belongs. Narrow angles are found in Asians and Eskimos, and hence they are more susceptible.
• White women are thrice as prone as white men, while black men and women are equally prone to it.

• The age group that is most susceptible is 55-65 years.
• It is found that usually, only one eye is affected by acute glaucoma and there are only 10% chances of both eyes being affected.
• Around 3 million people have lost their vision due to this disease.

Closed angle glaucoma is a dangerous disease which may result in blindness. Please make sure you consult an ophthalmologist immediately, in case you notice any of the symptoms of this disorder.