WHAT IS A CATARACT?
Cataracts are the most common cause of vision loss in people over age 40 and are the leading cause of blindness in the world. Almost all of us know someone with cataracts. Many take for granted that if they live long enough they will develop this eye problem, but you don't have to.
By age 80, more than half of all people in the United States either have a cataract or have had cataract surgery. In the U.S. 20.5 million suffer from cataract induced vision loss. Sadly, 50% of the 30-50 million cases of blindness worldwide result from un-operated cataracts. Cataracts occasionally occur in infants and young children and remain one of the leading causes of legal blindness for children in undeveloped countries worldwide.
Cataract occurs when there is an abnormal buildup of protein in the lens or lens capsule of the eye. There is a gradual yellowing and opacification of the lens. This clouding prevents light from entering the eye. It is similar to the vision blocking effect of frost or steam on a window. The lens of the eye is directly behind the pupil and works much like the lens of a camera. It focuses light onto the retina lining in the back of the eye where an image is recorded. This image is then passed through the retinal cells, into the optic nerve, and finally to the back of the brain where it is processed to become a visual image in the brain. An untreated cataract can also lead to glaucoma.
Symptoms of cataract can be: increased difficulty seeing at night, reduced intensity of colors, a brownish tint to vision making it difficult to identify blues & purples, blurred or hazy vision, increased sensitivity to glare from lights especially at night while driving, a change in the refractive error of the eye on vision testing.
WHAT IS GLAUCOMA?
Glaucoma is a group of diseases caused by increased pressure inside the eye which damages optic nerve and retina and can lead to progressive permanent vision loss. This increased pressure is caused by a buildup of aqueous humor, the fluid normally present in the front and rear chambers of the eye. This fluid normally drains from the eye through channels in the front of the eye in an area called the anterior chamber angle. When these channels are blocked, the aqueous humor does not filter normally and pressure builds in the eye. Normal intro ocular pressure (IOP) is 10-20 mmHG. Sometimes glaucoma changes can even occur with normal pressure.
The increased pressure of glaucoma disrupts normal blood flow in the eye, decreasing oxygen and nutrient delivery. This leads to impaired mitochondrial function and excessive production of free radicals. The free radicals destroy neighboring cell structures and ultimately initiate cell death which eventually leads to the blindness in glaucoma.
There is also a genetic predisposition so if family members have had glaucoma it is important to be very careful about getting eye pressure checks.
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