Sooner or later, all of us will experience some loss of vision. Whether we simply notice ourselves squinting more often at the sign across the street, or we find it increasingly difficult to see anything at all, our vision seems to become more fragile over time. The eye must tolerate continual exposure to dust, smoke, UV radiation, shampoo, dirty fingers, and a host of other hazards. That we are able to see at all is a testament to the capacity of biological systems to tolerate abuse. Below is a list of common visual disorders that can develop and progress with age.
http://www.nei.nih.gov/health/diabetic/retinopathy.asp#1
COMMON REFRACTIVE PROBLEMS:
Myopia- In myopia, or nearsightedness, the eyeball is elongated causing light rays to be focused in front of the retina. As a result, distance vision is blurred.
Hyperopia- In hyperopia, or farsightedness, the eyeball is too short, causing light rays to be focused behind the retina. As a result, near vision is blurred.
Presbyopia- Presbyopia is a type of farsightedness that occurs when the lens of the eye stiffens with age (typically experienced by most people as they reach 40 years of age).
Astigmatism- Those with an astigmatism have an overall inability to focus clearly at any distance because of uneven shapes/curvatures of the cornea, which bends light rays improperly. Light rays focus at multiple points producing blurred or double vision. Corneas with pronounced astigmatism are shaped more like a football than a well-rounded basketball.
COMMON VISION DISORDERS:
Cataract- A cataract is a clouding of the lens of the eye due to normal aging and changes in its chemical composition. This causes vision to be distorted or blurred, and colors my appear less vibrant.
Glaucoma- A person with glaucoma has an increased intraocular (fluid) pressure within the eye, which damages the optic nerve and retina. This increased pressure can result in a progressive loss of peripheral vision leading to blindness if not properly diagnosed and treated.
Macular Degeneration- Macular
degeneration is caused by a breakdown of cells from the macula, the part of the
retina responsible for sharp, central vision. Progressive deterioration of
the macula can lead to a complete loss of and/or blurred central sight. It
does not lead to complete blindness because the peripheral regions of the retina
remain unaffected. Details and color may not be perceived as well. There
are two types of macular degeneration (MD):
1. Dry type- the most common
type of MD; delicate tissues of the macula become thin and cease to function
properly.
2. Wet type- less common but
typically more damaging; growth of abnormal blood vessels behind the macula
which tend to hemorrhage or leak, resulting in the formation of scar tissue if
left untreated. In some cases, the dry type of MD can turn into the wet
type.
Diabetic Retinopathy- Diabetic retinopathy is a complication of diabetes and the leading cause of blindness. It occurs when diabetes damages the tiny blood vessels inside the retina, light-sensitive tissue at the back of the eye. Occurring in stages, changes to vision may not be readily noticed, but over time diabetic retinopathy can get worse and cause vision loss in both eyes.
Retinal Tear and Detachment- A retinal detachment or tear occurs when the retina is pulled away from its normal position in the back of the eye. The retina sends visual images to the brain through the optic nerve. When detachment/tearing occurs, vision is blurred. A detached or torn retina is a very serious problem that almost always causes blindness if left untreated.
*For more information on Eye Health, please visit the Nation Eye Institute's website: http://www.nei.nih.gov/
