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Cataract – Causes and Symptoms

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Cataract affects the most sensitive sensory organ of the body i.e. eye. A cataract is a development of a cloud in the eye’s natural lens. The cloud lies behind the iris and the pupil. The lens of eye works much like a camera lens. It focuses light onto the retina at the back part of the eye. These lens also adjusts the focus, which enables us to see things clearly either these are too close or far away.

The lens mostly consists of water and specific proteins (crystallins). These specific proteins in the lens perform specific functions. These are responsible for maintaining the clarity of the lens. As the age passes, the structures of these lens proteins reshape or some proteins start to combine together which result in clouding of the lens .This condition is called cataract which over the time grows. Larger cloud covers most of the lens making almost impossible to see.

Researchers are trying to gain the root cause with which these specific proteins make clusters in abnormal ways which causes lens cataracts. One recent theory suggests that the fragmented parts of these proteins combine with normal proteins, thus creating abnormal functioning. At birth or during early childhood, cataracts occurrence is very rare. It only occurs due to hereditary enzyme defects in this age.

Cataracts can be classified into three types depending on the location where these develop.

  • Nuclear cataract: This is the most common type and can be seen as it forms. This cloud forms in the nucleus or centre of the lens and is due to natural aging process.
  • Cortical cataract: This forms in the cortex of lens, gradually expands its formation from the outside of the lens to the center point. Mostly diabetic patients develop cortical cataracts.
  • Sub-capsular cataract: It begins from back of the lens. People with diabetes, high farsightedness, retinitis pigmentosa or those who using steroids extensively may develop a sub-capsular cataract.

Causes and symptoms

No one exactly knows why the eye lens changes with the passage of time and formation of cataracts. Researchers are trying to identify the factors that cause cataracts and methods to prevent it. Many studies have concluded that direct exposure to ultraviolet sunlight is linked to cataract development, so eye specialists recommend sunglasses and a wide-brimmed hat to reduce exposure in sunlight. Other types of radiation may cause cataract also e.g. a study conducted in Iceland 2005 suggests that commercial pilots have a high risk of developing nuclear cataract than non-pilots because they are more exposed to cosmic rays.

A cataract starts out from small cloud which grows larger gradually and affects your vision. You may feel that your vision is getting blurred a little, like looking through a cloudy piece of glass. A cataract makes sunlight or even lamp light seem too bright or glaring or you may find that when you drive at night oncoming headlights cause glaring more than normal and blur your vision. In cataract colors also lose their brightness, increased nearsightedness in addition to frequent change in eyeglass number and occasionally double impression in one eye. A change in glasses initially improve vision begins to weaken due to cataracts; however, as cataracts cover whole lens and gets denser, vision becomes more cloudy and stronger glasses or contact lenses will work no longer.

Cataracts grow gradually and usually painless or eye redness or other symptoms are associated with the extremely advanced condition of cataract.

Cataract Treatment

When symptoms start appearing, you may be able to enhance your vision while using new glasses to some extent, strong bifocals, magnification, appropriate lighting etc. Consult with an eye specialist or surgeon when your feel that cataract is seriously impairing your vision and affecting your routine life. Many old people think that poor vision is an inevitable fact of aging, but cataract surgery is a simple procedure, relatively pain free and successful in vision restoration.

These days it is the most common performed surgery in the U.S, with above than 3 million Americans undergoing cataract surgery every year. 9 out of 10 people who have cataract surgery regain good vision, somewhere between 20/20 and 20/40.

The cataract surgery procedure is performed in either a hospital or in an ambulatory surgery center. The most common method of cataract surgery available today is called phacoemulsification. By using an operating microscope, surgeon makes a very small incision in the upper surface of the eye. A thin ultrasound probe is inserted into the eye which uses ultrasonic vibrations to degenerate the clouded lens. These macro fragments are then sucked out through the same ultrasound probe. An artificial lens is placed into the bag after cataract removal. This intraocular lens (IOL) is helpful in eye focus after operation.

There are three basic techniques for cataract surgery:

Phacoemulsification: The most common method of cataract removal as explained above. This is most advanced form, cataract surgery take less than 30 minutes for completion and usually requires very minimal sedation, no stitches required to close the wound, and no post operative eye patch.

Extracapsular cataract surgery: This procedure is needed where cataract is too dense to dissolve or does not have modern phacoemulsification technology. This requires a larger incision so that the cataract can be removed in a single piece. This technique requires a number of stitches to close the comparatively large wound, and visual restoration is often too slow. It also requires an eye patch after surgery.

Intracapsular cataract surgery: This technique requires an even larger wound than extracapsular surgery. This technique requires the IOLs to be placed, in front of the iris. This method is rare today but still useful in cases of significant trauma.

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1 comment

Herry May 18, 2008 - 4:57 am

Cataract can be caused by the strong light. Try not to stay long time in front of computer to avoid eye version get affected

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