Others
Cataract
cataract is a clouding that develops in the crystalline lens of the eye or in its envelope, varying in degree from slight to complete opacity and obstructing the passage of light. Early in the development of age-related cataract the power of the lens may be increased, causing near-sightedness (myopia), and the gradual yellowing and opacification of the lens may reduce the perception of blue colours. Cataracts typically progress slowly to cause vision loss and are potentially blinding if untreated.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.
Cataracts can form at any age. The most common type of cataracts is age-related cataract. These develop as people get older. In younger people cataracts can result from conditions such as diabetes, certain medications and other longstanding eye problems. Cataracts can also be present at birth. These are called congenital cataracts.The lens is made mostly of water and protein. Specific proteins within the lens are responsible for maintaining its clarity. Over many years, the structures of these lens proteins are altered, ultimately leading to a gradual clouding of the lens. Rarely, cataracts can present at birth or in early childhood as a result of hereditary enzyme defects, and severe trauma to the eye, eye surgery, or intraocular inflammation can also cause cataracts to occur earlier in life.
During the diagnostic examination, an ophthalmologist will carefully measure the shape, size and general health of the eye to determine whether a lens implant will be effective. In the relatively small number of cases where it won’t be, eye-glasses or contact lenses will improve vision after traditional cataract surgery. Glasses, while used for years, have drawbacks. Their extreme thickness makes them unattractive and heavy. Magnification and distortion of the visual image causes objects to appear closer and 25 percent larger than they are. Peripheral vision may be reduced. Contact lenses provide fairly good vision, but many elderly people have trouble inserting, removing and cleaning them.
