Glaucoma¹

Glaucoma generally involves increased fluid pressure inside the eye (intraocular pressure), which damages the optic nerve and causes partial vision loss and can progress to blindness.

Causes, incidence, and risk factors

Glaucoma is the third most common cause of blindness in the US. There are four major types of glaucoma:

• Closed angle (acute) glaucoma
• Open angle (chronic) glaucoma
• Congenital glaucoma
• Secondary glaucoma

Although all four types of glaucoma are characterized by increased pressure within the eyeball, and therefore all can cause progressive damage to the optic nerve, a rare form of chronic glaucoma occurs with normal eye pressure.

Increased pressure occurs when the fluid within the eye (called aqueous humor) does not drain properly. The pressure pushes on the junction of the optic nerve and the retina at the back of the eye. This reduces the blood supply to the optic nerve, which carries visual information from the eye to the brain.

This loss of blood supply causes the individual nerve cells to progressively die. As the optic nerve deteriorates, blind spots develop in the field of vision. Peripheral (side) vision is affected first, followed by central (front) vision. Without treatment, glaucoma can eventually cause blindness.

Closed angle (acute) glaucoma may occur in people who were born with a narrow angle between the iris and the cornea (the anterior chamber angle). This is more common in people who are farsighted (they see objects in the distance better than those which are close up). The iris may slip forward and suddenly close off the exit of aqueous humor, and a sudden increase in pressure within the eye follows.

Symptoms of pain, redness, nausea, and visuon loss develop rapidly. Angle closure may be provoked in susceptible persons by the use of drops that dilate the eyes. Attacks may also develop without any obvious triggering event. This is more common in the evening because the eye's pupils naturally dilate in dim light.

Open angle (chronic) glaucoma is by far the most common type of glaucoma. In open angle glaucoma, the iris does not block the drainage angle as it does in acute glaucoma. Instead, the fluid outlet channels within the wall of the eye gradually narrow with time. The disease usually affects both eyes, and over a period of years the consistently elevated pressure slowly damages the optic nerve.

Chronic glaucoma has no early warning signs, and the associated loss of peripheral vision occurs so gradually that it may go unnoticed until a substantial amount of damage and vision loss have occurred. The only way to diagnose glaucoma early is through routine eye examinations.

Secondary glaucoma is caused by other diseases, including eye diseases such as uveitis, systemic diseases, and drugs such as corticosteroids.

Congenital glaucoma, which is present at birth, is the result of defective development of the fluid outflow channels of the eye. Surgery is required for correction. Congenital glaucoma is often hereditary.

Risk factors depend on the type of glaucoma.

For chronic glaucoma, risk factors include:

• Age over 40
• Family history of glaucoma
• Diabetes
• Nearsightedness

People with a family history of open angle glaucoma have twice the risk of developing open angle glaucoma as those who do not. African-Americans have four times the risk of developing open angle glaucoma compared to Caucasian Americans. It is estimated that 1% to 2% of people over 40 have chronic glaucoma, with about 25% of cases undetected.

Risk factors for acute glaucoma include:

• Older age
• Family history of acute glaucoma
• Farsightedness
• Use of systemic anticholinergic medications (such as atropine or eye dilation drops) in a high-risk individual

Acute, congenital, and secondary glaucoma are much less common than chronic glaucoma.

Symptoms

ACUTE

• Severe eye pain, facial pain
• Loss of vision
• Cloudy vision with halos appearing around lights
• Red eye
• Fixed, nonreactive pupil
• Nausea and vomiting

CHRONIC

• Gradual loss of peripheral vision
• Blurred or foggy vision
• Mild, chronic headaches
• Seeing rainbow-colored halos around lights

Note: Most people with chronic glaucoma have no symptoms until peripheral visual loss is severe

CONGENITAL

• Tearing
• Sensitivity to light
• Redness of the eye
• Corneal haziness
• Enlarged cornea

1. Source: Medline: NIH Medical Encyclopedia

Preventive measures and Alternative treatment for Glaucoma

Eye Care Naturally includes a chapter on glaucoma which describes in non-technical language what glaucoma is and what steps you need to take to prevent glaucoma, slow down its progression, and in some cases, arrest it. The author, nutritional eye care specialist Dr. E. Michael Geiger, is an optometrist for many years with extensive experience in eye conditions and nutrition.

In the chapter on glaucoma in "Eye Care Naturally" Dr. Geiger details how to handle glaucoma and improve eye health through researched advice on eating properly, taking the correct nutritional supplements and adopting a suitable lifestyle. It is must reading for anyone predisposed to glaucoma, that is a glaucoma suspect or that currently has the disease. It is a MUST read!