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Information on eye diseases and disorders was

obtained at the St. Lukes Eye Clinic Website

www.stlukeseye.com

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Blindness Facts

Just over 3% of the U.S. population have a visual impairment.

Less than 1% of the U.S. population have legal blindness.

Legal Blindness: Visual acuity of 20/200 or less, or reduction of vision field to 20 degrees or less, in the better eye, with corrections.

Congenital refers to someone with vision loss since birth.

Acquired refers to someone with vision loss appearing later in life.

Total Blindness refers to someone who has complete vision loss.

Less than 40% of people who are blind are “total.”

Almost all cases of blindness are caused by eye disease. Less than 3% are due to injuries.

There are five main types of blindness 1) Macular Degeneration 2) Glaucoma 3) Cataracts 4) Diabetic Retinopathy 5) Retinitis Pigmentosa.

With visual impairments that are progressive (e.g. glaucoma, diabetes), even moderate drinking can worsen the condition.

Only about 10% of people who are blind read Braille.

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Macular Degeneration

A degenerative condition of the macula

(the central retina). It is the most common

cause of vision loss in the United States

in those 50 or older, and its prevalence

increases with age. It is caused by hardening

of the arteries that nourish the retina.

This deprives the sensitive retinal tissue of oxygen and nutrients

that it needs to function and thrive.

As a result, the central vision deteriorates.

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Patients with wet macular degeneration

develop new blood vessels under the retina.

This causes hemorrhage, swelling,

and scar tissue but it can be treated with

laser in some cases.

Macular Degeneration

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Macular Degeneration

Dry macular degeneration, although more common, typically

results in a less severe, more

gradual loss of vision.

It is characterized by drusen and

loss of pigment in the retina.

Drusen are small, yellowish deposits that form

within the layers of the retina.

Drusen

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Diabetic Retinopathy

The effect of diabetes on the eye is

called diabetic retinopathy. Over time,

diabetes affects the circulatory system

of the retina.

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The earliest phase of the disease is known as background diabetic retinopathy. In this phase, the arteries in the retina become weakened and

leak, forming small, dot-like hemorrhages.

The next stage is known as proliferate diabetic retinopathy. In this stage, circulation problems cause areas of the retina to become oxygen-deprived or ischemic. New, fragile, vessels develop as the circulatory system attempts to maintain adequate oxygen levels within the retina. This is called neovascularization. Unfortunately, these delicate vessels hemorrhage easily.

Diabetic Retinopathy

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When cataracts are mentioned,

people often think of a film that grows

on their eyes causing them to see

double or blurred images. However,

a cataract does not form on the eye,

but rather within the eye.

Cataracts

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A cataract is a clouding of the natural lens, the part of the eye responsible for focusing light and producing clear, sharp images. The lens is contained in a sealed bag or capsule. As old cells die they become trapped within the capsule. Over time, the cells accumulate causing the lens to cloud, making images look blurred or fuzzy. For most people, cataracts are a natural result of aging.

Cataracts

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GlaucomaGlaucoma is a disease caused by increased

intraocular pressure (IOP) resulting either

from a malformation or malfunction of the

eye’s drainage structures. Left untreated,

an elevated IOP causes irreversible damage

the optic nerve and retinal fibers resulting in

a progressive, permanent loss of vision.

However, early detection and treatment can slow,

or even halt the progression of the disease.

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Glaucoma

The above photos show progressive optic nerve damage

(indicated by the cup to disc ratio) caused by glaucoma.

Notice the pale appearance of the nerve with the 0.9

cup as compared to the nerve with the 0.3 cup.

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Retinitis Pigmetosa

Retinitis pigmentosa (RP) is a rare,

hereditary disease that causes the rod

photoreceptors in the retina to gradually degenerate.

The classic sign of RP is clumps of pigment in the

peripheral retinal called "bone-spicules."

Retinitis Pigmetosa

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