Glaucoma

General Illness Information

Medical Term:
GLAUCOMA

Common Name: None Specified

Description: Glaucoma is a term applied to a number of conditions causing optic nerve damage often in  association   with increased intraocular pressure ( increased  pressure in the eyeball ) causing damage to the optic nerve and resulting in potential loss of vision.

Glaucoma is a disease of pressure and adequate lowering of intra-ocular pressure almost always stops optic nerve damage.

There are four main forms: Primary open-angle glaucoma, Congenital glaucoma, Secondary glaucoma, Angle closure glaucoma.

Glaucoma is a major cause of blindness. It affects approximately 4% of the population above the age of 40, with over 90% of these glaucomas being chronic open-angle glaucomas. Affects both sexes equally. Can occur at any age , but more commonly presents after age 40.

Causes: In most cases, cause is unknown; however it sometimes runs in families. 

The eye has two chambers- the front (anterior) and the back (posterior) chambers which are filled with thin fluid called the aqueous humor. Normally the fluid is produced in the posterior chamber, passes through the pupil into the anterior chamber, and then drains from the eye through the outflow channels.

 If the flow of the fluid is interrupted, usually by an obstruction that prevents the fluid  from flowing out of the anterior chamber, pressure increases. This type of glaucoma is called closed-angle glaucoma. 

In the open-angle glaucoma, the outflow channels are open- this is the commonest form of glaucoma , making up for 70% of all glaucoma cases and is a familial disease.

Congenital glaucoma is a relatively  rare form and is caused by a congenitally imperfect aqueous humor drainage mechanism. However, its diagnosis is urgent because timely surgery prevents permanent visual loss. 

Secondary glaucoma is the result of damage to the drainage mechanism caused by other diseases affecting the eye or injury to the eye.

Prevention: Make sure that tension in the eyeball is measured with every eye examination (at least once a year after age 40). 

Seek medical advice for any changes in your vision

Signs & Symptoms

Angle closure glaucoma is a medical emergency. Symptoms are:

Severe throbbing eye pain and headache.

Redness in eye.

Blurred vision.

Halos around lights.

Tender, firm eyeball.

Fixed dilated pupil. Hazy cornea.

Nausea/vomiting in severe cases.

Primary open angle glaucoma:

Gradual onset.

Loss of peripheral vision.

Blurred vision.

Halos around lights.

Difficulty with color perception

Poor night vision.

Risk Factors

Adults over 40.

Family history of acute or chronic glaucoma.

Diabetes mellitus.

African-American descent.

Myopia (near-sightedness).

Diagnosis & Treatment

Diagnosis can be made by eye examination studies such as tonometry (measurement of pressure within the eye) and ophthalmoscopy and visual field testing.

The disease cannot be cured, but it can be controlled. For the most part, medications can lower the pressure enough to protect the optic nerve from future damage and possible loss of vision. Glaucomatous visual loss cannot be restored. But if the intraocular pressure is reduced substantially, progressive visual loss may be prevented in a majority of cases.

General Measures:

Management of all forms of glaucoma involves lowering the intraocular pressure.

Treatment of  chronic open angle glaucoma (COAG)  is directed at lowering the intraocular pressure  by medical therapy. The disease cannot be cured, but control can be obtained by decreasing the rate of aqueous secretion, by increasing the rate of aqueous outflow, or by combination of the two. Usually  medical therapy medical therapy is able to reduce the pressures sufficiently to protect the optic nerve from further damage and ultimate visual field loss and visual loss. Early detection and adequate treatment can prevent visual loss in virtually every case. Laser surgery can be performed if eye drops do not control the disease.

Treatment of primary angle-closure glaucoma- intravenous medications are required for the acute form. Definitive treatment is laser surgery once the intraocular pressure has been normalized.

Medications:

Eye medications to lower pressure inside the eye will be prescribed. Follow the instructions and schedule carefully, even if symptoms subside

Activity:

No restrictions. However, in the acute form of primary angle-closure glaucoma bed rest is advised till the attack subsides.

Diet:

No restrictions.

Possible Complications :

Loss of vision before other symptoms begin.

In primary angle-closure- 

Damage to the cornea.

Cataracts.

Displacement of the lens (subluxation of the lens).

Central retinal vein occlusion.

Optic nerve atrophy.

Prognosis

Symptoms can usually be controlled with treatment. Glaucoma treatment is lifelong. Vision is usually not impaired permanently, if glaucoma is treated.

 

Other

‘Nothing Specified’.

Posted by RxMed