ACUTE GLAUCOMA
Unlike POAG (Primary Open-Angle Glaucoma), where the IOP increases slowly, in acute angle-closure, it increases suddenly. This sudden rise in pressure can occur within a matter of hours and become very painful. If the pressure rises high enough, the pain may become so intense that it can cause nausea and vomiting.The eye becomes red, the cornea swells and clouds, and the patient may see haloes around lights and experience blurred vision.
An acute attack is an emergency condition. If treatment is delayed, eyesight can be permanently destroyed. Scarring of the trabecular meshwork may occur and result in chronic glaucoma, which is much more difficult to control. Cataracts may also develop. Damage to the optic nerve may occur quickly and cause permanently impaired vision.
Many of these sudden `attacks´ occur in darkened rooms, such as movie theaters. If you recall, darkened environments cause the pupil to dilate, or increase in size. When this happens, there is maximum contact between the eye´s lens and the iris. This further narrows the angle and may trigger an attack. But the pupil also dilates when one is excited or anxious. Consequently, many acute glaucoma attacks occur during periods of stress. A variety of drugs can also cause dilation of the pupil and lead to an attack of glaucoma. These include anti-depressants, cold medications, antihistamines, and some medications to treat nausea.
Acute glaucoma attacks are not always full blown. Sometimes a patient may have a series of minor attacks. A slight blurring of vision and haloes (rainbow-colored rings around lights) may be experienced, but without pain or redness. These attacks may end when the patient enters a well lit room or goes to sleep -- two situations which naturally cause the pupil to constrict, thereby allowing the iris to pull away from the drain.
An acute attack may be stopped with a combination of drops which constrict the pupil, and drugs that help reduce the eye´s fluid production. As soon as the IOP has dropped to a safe level, your ophthalmologist will perform a laser iridotomy. A laser iridotomy is an outpatient procedure in which a laser beam is used to make a small opening in the iris. This allows the fluid to flow more freely. Drops will be used to anesthetize your eye and there is no pain involved. The entire procedure should take less than thirty minutes. Laser surgery may be performed prophylactically on the other eye, as well. Since it is common for both eyes to suffer from narrowed angles, operating on the unaffected eye is done as a preventive measure.
Routine examinations using a technique called gonioscopy can predict one´s chances of having an acute attack. A special lens which contains a mirror is placed lightly on the front of the eye and the width of the angle examined visually. Patients with narrow angles can be warned of early symptoms, so that they can seek immediate treatment. In some cases, laser treatment is recommended as a preventive measure.
Not all angle-closure glaucoma sufferers will experience an acute attack. Instead, some may develop what is called chronic angle-closure glaucoma. In this case, the iris gradually closes over the drain, causing no overt symptoms. When this occurs, scars slowly form between the iris and the drain and the IOP will not rise until there is a significant amount of scar tissue formed -- enough to cover the drainage area. If the patient is treated with medication, such as pilocarpine, an acute attack may be prevented, but the chronic form of the disease may still develop.