What Are the Causes and Treatments of Cataract

Cataracts are a significant cause of blindness is Australia, accounting for nearly 30 percent of cases. The person notices a gradual painless failure in sight or sometimes the blurring of vision. At first the vision can be restored with spectacles but, within months or years, the lens becomes completely opaque and the sight is severely impaired. When this happens a light shone in the pupil of the eye reveals a white opacity.

Causes

The lens of the eye has no blood supply and the majority of its cells cannot divide. Their only function is to remain transparent, but their response to damage or a defect--be it disordered metabolism, radiation, inflammation or a fault in development--is to become opaque. However, the large majority of cataracts are a result of simple senile degenerative change rather like the whitening of hair which is due to degeneration of the epithelial cells of the hair. In the majority of people over 60 years old there is some degree of lens opacity but in only a few of them does the opacity become sufficient to be called cataracts.

The other causes of cataracts are numerous and varied. The incidence of these causes varies greatly from country to country. The causes include accidents, such as perforating wound involving the lens capsule, or protracted inflammation of the iris and the ciliary body producing toxins. Diabetics are particularly liable to earlier development of cataract of the senile variety.

If there is a low blood calcium caused by deficiency of the parathyroid gland, cataracts may developed. In industry, prolonged excessive exposure to infra-red radiation, gamma radiation or heat may cause cataracts, so appropriate precautions such as wearing protective goggles should be taken. Drugs which cause cataracts include prolonged high doses of corticosteroids including phenothiazines such as chlorpromazine.

Babies may be born with cataracts which affect one or both eyes. Often the cause of these cataracts is not known but German measles (rubella) in the mother in the first three months of pregnancy ans a metabolic disorder called galactosemia are known causes. Generally speaking it is accepted that although some congenital cataracts are hereditary many more are a result of some intrauterine influence present during the formation of the lens. Babies with congenital cataract often have some other defect with in the eye.

Treatment

The usual treatment of cataracts in adults is to remove them surgically. In the operation the lens is removed from the lens capsule. Methods first employed in the 1950s use pancreatic enzymes to release the lens from its attachment so it more easily removed. Freezing techniques and ultrasonic probes are also employed.

Recently lens have been replaced by an artificial lens, but some have caused reactions within the eye. Though not generally accepted, lens implants are gaining more favor. Techniques which dissolve the lens contents and suck them out have also been pioneered, and research continues.

Cataract removal in 95 per cent successful in some, though not normal, vision is regained. The treatment and removal of cataracts is a delicate operation and a task for an eye surgeon (ophthalmologist).

On the whole surgical treatment is not undertaken unless the vision loss is significant and the cataract 'mature'; however ophthalmologists differ in their criteria. Congenital cataracts in babies are often not treated surgically unless they are bilateral, there is no other eye disorder and they are sufficiently severe to cause complete blindness.

Source:

Diagnosis: Cataract, by Robert T. Lacy, pp 23 -25, 1982

Cataract - Causes, treatment and tips, buzzle , by Nilesh Parekh, Oct. 2004