Glaucoma Risk Factor Analysis Predicts Blindness

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Using glaucoma risk factor analysis to predict and prevent blindness is a recent prevention measure for early detection of glaucoma, which is the second leading cause of blindness and partial vision loss in the United States. Scientists recently report a statistical analysis program they’ve created that predicts your likelihood of developing the most common type of glaucoma - Open Angle Glaucoma.

Glaucoma is an eye disease that cannot be prevented. Furthermore, once glaucoma has developed its vision-damaging effects cannot be reversed. However, what can be done is early diagnosis and treatment to control the extent of the eye disease and its effect on vision loss. The majority of people who have glaucoma and follow a treatment plan and regular monitoring by a physician typically do not become totally blind from glaucoma.

Glaucoma results when too much fluid pressure builds up inside the eyeball between the cornea and the iris. Pressure within the eyeball is called intraocular pressure. When intraocular pressure is too high, it damages the optic nerve leading to eventual vision loss that will progress to blindness if left untreated.

The fluid inside the eye is called the aqueous humor and its normal pressure is maintained as fluid flows in and out through a mesh-like channel in the eye called the trabecular meshwork. If the trabecular meshwork becomes clogged or blocked in some way, then fluid builds up with increasing pressure that is relatively high. Blunt trauma or chemical injury to the eye as well as infection and inflammation can also cause glaucoma to develop. However, the cause of glaucoma is usually genetic and is passed on from parents to their children.

The first symptom of glaucoma is typically limited to loss of peripheral or “side” vision. However, by the time a patient notices the loss of peripheral vision, major nerve damage has already occurred. Other symptoms of glaucoma may include:

• Vision loss
• Redness in the eye
• Nausea
• Eye pain
• Tunnel vision
• Seeing halos around lights
• Eye that looks hazy (particularly in infants)

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The most common type of glaucoma is open-angle glaucoma (OAG)—also known as wide-angle glaucoma—where the eyeball appears normal, but is under high intraocular pressure because the aqueous humor does not flow through the trabecular network properly in the eyeball.

Because of the lateness in diagnosing open angle glaucoma based on loss of peripheral vision, scientists at University of Medicine and Dentistry of New Jersey, Newark have devised a program that incorporates statistical analysis with select risk factors of OAG that allows health professionals to determine whether a patient may develop OAG before optic nerve damage can occur.

Data from 400 patients with varying degrees of eye disease was collected and analyzed to determine which risk factors were the most predictive of open-angle glaucoma disease development. What the researchers found was that some of the predictive factors included a patient’s smoking history, age, current visual field test results, the presence of a localized notch or thinning of the neuroretinal rim, and an increased cup-to-disk ratio, which is a measure of restriction of the optic nerve at the back of the eye.

For example, the likelihood of developing OAG increases by 91% with an increase in cup-to-disc ratio of 0.1; a 3% increase depending on age; a 4.36 fold increase for patients with an abnormal Humphrey field test result; and, the presence of a notch or thinning of the neruoretinal rim.

The researchers believe that their statistical analysis of risk factors will provide a predictive diagnosis before the onset of glaucoma, but that family history, medical history, current medications, geographic location, visual field test and ocular examination results should continue to be considered toward diagnosis and prognosis for OAG.

For more info about common eye diseases that come with aging see http://www.emaxhealth.com/8782/eyes-have-it-six-vision-changes-come-aging

Source: Duo Zhou et al. “Risk factors for open angle glaucoma: analyses using logistic regression” Int. J. Medical Engineering and Informatics 2011, 3, 203-222

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Comments

Good to know as we get older and need to be checked for glaucoma