A cataract is a clouding of the
eye's natural lens, which lies behind the iris and the pupil.
Cataracts are the most common
cause of vision loss in people over age 40 and is the principal cause of
blindness in the world. In fact, there are more cases of cataracts worldwide
than there are of glaucoma, macular
degeneration and diabetic retinopathy combined.
Types of Cataracts include :
- Subcapsular Cataract : It occurs at the back of the
lens. People with diabetes or those taking high doses of steroid medications
have a greater risk of developing a subcapsular cataract.
- Nuclear Cataract : It forms deep in the central zone
(nucleus) of the lens. Nuclear cataracts usually are associated with aging.
- Cortical Cataract : It is characterized by white, wedge-like
opacities that start in the periphery of the lens and work their way to the
center in a spoke-like fashion. This type of cataract occurs in the lens
cortex, which is the part of the lens that surrounds the central nucleus.
Symptoms of Cataract
A cataract starts out small and at first has little effect
on your vision. You may notice that your vision is blurred a little, like
looking through a cloudy piece of glass or viewing an impressionist painting.
A cataract may make light from the sun seem too bright or
glaring. Or you may notice when you drive at night that the oncoming headlights
cause more glare than before. Colors may not appear as bright as they once did.
Different type of cataract has different symptoms and different
effect on your eye sight. When a nuclear cataract first develops, it can bring
about a temporary improvement in your near vision, called "second
sight."
Unfortunately, the improved
vision is short-lived and will disappear as the cataract worsens. On the other
hand, a subcapsular cataract may not produce any symptoms until it's
well-developed.
Causes of
Cataracts
The lens inside
the eye works much like a camera lens, focusing light onto
the retina for clear vision. It also adjusts the eye's focus, letting
us see things clearly both up close and far away.
The lens is mostly made of water
and protein. The protein is arranged in a precise way that keeps the lens clear
and lets light pass through it.
But as we age, some of the
protein may clump together and start to cloud a small area of the lens. This is
a cataract, and over time, it may grow larger and cloud more of the lens,
making it harder to see.
Some factors that can cause cataracts or are associated with
cataract development :
- Ultraviolet Radiation from Sunlight and Other Sources
- Diabetes
- Hypertension
- Obesity
- Smoking
- High Myopia
- Family History
- Prolonged use of Corticosteroid Medications
- Statin medicines used to reduce Cholesterol
- Previous Eye Injury or Inflammation
- Previous Eye Surgery
- Hormone Replacement Therapy
- Significant Alcohol Consumption
Many cataracts are caused by
oxidative changes in the human lens. This is supported by nutrition studies
that show fruits and vegetables high in antioxidants may help prevent
certain types of cataracts.
Prevention of Cataract
- Certain nutrients and nutritional
supplements may reduce your risk of cataracts.
- Many studies shown that higher dietary intakes of vitamin E
and the carotenoids lutein and zeaxanthin from food and supplements can
decrease risks of cataract. Vitamin E found in higher quantities in almonds, sunflower
seeds and spinach. Good sources of lutein and zeaxanthin include spinach, kale
and other green, leafy vegetables.
- Similarly antioxidant vitamins such as vitamin C and foods
containing omega-3 fatty acids may reduce cataract risk.
- You can wear protective sunglasses
that block 100 percent of the sun's UV rays, to reduce your risk of cataracts
development.
Treatment of Cataract
- When symptoms begin to appear, you may be able to improve your vision for a while using new glasses, strong bifocals, magnification, appropriate lighting or other visual aids.
- When your cataracts have progressed enough to seriously impair your visions, you must go for simple eye surgery. Many people consider poor vision an inevitable fact of aging, but cataract surgery is a simple, relatively painless procedure to regain vision.
- Cataract surgery is very successful in restoring vision. Nine out of 10 people who have cataract surgery regain very good vision.
- During surgery, the surgeon will remove your clouded lens and replace it with a clear, plastic intraocular lens (IOL).
- Presbyopia-correcting IOLs (plastic intraocular lens) potentially help you see at all distances, not just one. Another type of IOL blocks both ultraviolet and blue light rays, which research indicates may damage the retina.
