Glaucoma Prevention and Treatment : Acute Glaucoma

by Food and Drug Administration (FDA)

(Page 2 of 3)

Timoptic's century-old predecessor, pilocarpine, requires more frequent use to do its job, increasing drainage of aqueous fluid in both open- and closed-angle glaucomas. Pilocarpine is a miotic, designed to increase aqueous fluid drainage. Because miotics work by making the pupil smaller, they can result in dim vision and may increase the risk of cataracts.

Another class of medications, adrenergic agonists, such as epinephrine, also increases aqueous humor drainage, with possible side effects of allergic reactions, blurred vision, headache, and increased heart rate. Alpha adrenergic agonists decrease aqueous humor production after surgery or aid patients taking maximum dosages of other medications. Side effects include red eyes, allergic reactions, and dry mouth.

Diamox carbonic anhydrase inhibitor tablets, like beta blockers, decrease production of aqueous fluid, but these drugs seem to provoke more prominent side effects in some people, including mental depression, kidney stones, tingling in the hands and feet, and sometimes anemia.

FDA's May 1995 approval of a Carbonic Anhydrase Inhibitor in eye drop form as Trusopt (dorzolamide) provides a medication that may have fewer and reduced incidence of these severe side effects.

Since reactions to medications vary so much from person to person, a drug that causes one individual problems may be easily tolerated by another. An appropriate drug regimen, therefore, needs to be worked out carefully between patient and health professional.

Glaucoma medications are potent drugs. Those who take them should consult a pharmacist to be certain that they won't interact adversely with any other prescriptions or over-the-counter drugs being taken. For example, some over-the-counter products, including decongestants, may not be suited for people at risk of glaucoma.

Acute (Closed-Angle) Glaucoma

A century after Milton gradually lost his sight, composer Johann Sebastian Bach went blind in a violent flash, probably from acute (closed-angle) glaucoma. Bach thought he aggravated his weak vision by a lifetime of copying music in the dim light of church organ lofts; his portrait shows a characteristic squint. Though a surgeon claimed to have operated successfully on Bach's eyes, the composer's vision failed again in a few days. He died a few months later, after a futile — and possibly harmful — second operation.

Acute glaucoma may seem the opposite of open-angle because it erupts in violent attacks and intense pain, rather than emerging subtly. Yet patients may not notice minor preliminary episodes, which pave the way for serious seizures. People beset by a major seizure must get to an ophthalmologist, or at least a hospital emergency room, promptly to save their vision.

Monitoring can protect people prone to acute glaucoma from major attacks.

Acute glaucoma attacks are emergencies because aqueous fluid gets trapped in the angle of the eye suddenly. Having nowhere to go, its abrupt backup can damage the optic nerves, eventually squashing them irreparably.

Regular, thorough eye checkups can detect the risk of acute glaucoma. High IOP, family history, and other indicators resemble those for common glaucoma, but very farsighted people and those of Asian descent are most vulnerable to angle-closure glaucoma. Once a major angle-closure attack seems imminent, preventive laser surgery is advisable, since an attack can damage the eye quickly.

Regular monitoring of people diagnosed with narrow-angle conditions looks for increased IOP or tissue damage. Telltale symptoms of an attack include blurred vision, halos around lights, and eye pain sharp enough to induce vomiting. The eye becomes reddened, feeling as if it could burst (though it can't). Persons experiencing such attacks should go immediately to an ophthalmologist or an emergency room, ideally calling in advance to ready staff to receive a case of closed-angle, acute glaucoma.

Emergency procedures use eye drops and clinical eye massage to reduce IOP and prevent the eye from hardening. Once stabilized, the patient may have laser surgery to create an artificial opening for aqueous fluid to drain. Acute glaucoma usually attacks one eye before the other, so laser surgery on the unaffected eye may be recommended at the time to forestall a second attack there.

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.