Saturday, 23 July 2011

Understanding Cataract

Published in "Panorama"

Understanding Cataract

Sameer’s parents could not believe their ears when the pediatrician told them that their new-born had cataract! 7 year old Steve developed instant cataract when he was hit by a dart on the eye. Sushil is still on the right side of 30; but he was diagnosed as having cataract when he went to see his physician for a blurred vision!

Well, if you know how your camera works, you will realize that cataract is not entirely and exclusively an age-related condition, as is commonly believed! The human eye is very much like a camera: both have a lens to focus objects. If the camera lens is hit by fungus, pictures will be hazy even if your focus had been good. Similarly, if the eye lens becomes opacified, you begin to see objects, fuzzy. The retina of the eye is like the camera film which catches the images. Should the film roll be of poor quality, the resulting pictures are bad. Similarly, if the retina is damaged by diseases like diabetes or hypertension, your vision is not good. The eye lens and the retina, together with the cornea, result in good vision. The cornea or the curvature of the eye is like the ultraviolet filter fitted in front of the lens in a camera. If the filter is smeared or unclear in some way, the resulting photos are not good. In much the same way, if the cornea be scratched or scarred, your vision is blurred.

“Any defect in the eye lens, an opacification of the lens, is cataract; it could be very small like a spot which is not significant, or it could be the entire lens being involved wherein it is fully opaque”, explains Dr.Mohammed A,P, Opththalmologist, Al Rafa Poly Clinic Dubai.
A number of factors can result in cataract, though the commonest cause may be the chemical changes in the lens that partially result from the normal process of aging. But these cataracts can rarely occur as early as age 30, says Dr.Azim, Specialist Eye Surgeon, Prime Medical Centre, Dubai.

In majority of people, cataract is a part of ageing and may begin around the mid forties. What happens in the human eye is like the white of an egg getting boiled! The human lens and the egg white are made up of proteins and water. The egg white which is transparent when raw, turns white and opaque when boiled. Similarly, when the body ages, either as a natural process or due to certain diseases, the transparent protein in the human lens starts becoming opacified in varying degrees. This opacification is cataract, explains, Dr.Azim. Once formed, the process cannot be reversed, emphasize the specialists.

Is it true that ageing necessarily brings on cataract? “NO”, says Dr.Azim. “For some people with age, cataract appears very late. But in some people this may occur early with age and this is solely gene dependent. Of course, occupation, food and climate have some influence.”

It is not uncommon these days to find younger ages of people, like Sushil, getting affected with cataract, opine the doctors. Elaborating, Dr.Azim explains, “There is now evidence that prolonged exposure to ultraviolet light can contribute to cataract formation. More exposure to radiation, diet habits and some bio-chemical agents have been identified which result in faster progression of the condition.”

The other category of people prone to early cataract are those suffering from certain diseases like diabetes, iridocyclitis and individuals having some intra-ocular inflammation. In these instances, the disease itself can affect the lens, leading to cataract. Alternatively, the disease accelerates the ageing process, thus leading to cataract. Any eye infections cause toxins in the eye to circulate more, exposing the lens to these toxins. And anything which is exposed to toxins, becomes affected early and this is as true of cataract, opines Dr.Azim.
Drug induced cataract is particularly common in individuals who have been taking prolonged medication, especially steroids, for chronic conditions like asthma, arthritis and other ailments.

Trauma and injury-induced cataract can affect anyone regardless of age and is generally found to be common in young people, reveals Dr.Azim. Dr.Azim explains, “When the cataract actually forms depends on the type of injury. If the injury is by a sharp object in which the eye is penetrated, as in the case of Steve, the cataract develops instantaneously. Typically in blunt injuries as caused during boxing bouts, it takes time for the cataract to develop.”

As in the case of Sameer, congenital cataract, a rare condition, is present at birth and is usually recognized by a white spot or squint in the infant’s eye. “The condition normally occurs when a pregnant mother is infected with measles or German Measles or she is malnourished,” explains Dr.Azim. “Also, this form of cataract is more common in offsprings from cousin marriages, especially if certain diseases run in their families. If the child has got cataract which is mature and dense, and if it is not properly treated and on time, (by the age of six years) even when treated later on by very successful surgery, the child might not get useful vision.”

Dr.Mohammad adds that cataracts occurring at birth could also be the result of inborn errors of metabolism and heredity.

What are the symptoms of cataract? The individuals may complain of blurred vision, distortion of vision, glare from bright lights and gradual loss of vision. He may show signs of plus or minus eye power, depending on where in the lens, the changes are occurring, says Dr.Mohammad.

Is cataract a preventable condition? The condition is neither preventable nor reversible, according to the specialists.

However, one can prevent some of the risk factors leading to cataract, says Dr.Azim. These include:
1. Those who are forcibly exposed to direct sunlight, should use good quality ultraviolet lenses to retard the development of cataract.
2. People working in hazardous environments should wear protective goggles.
3. Those on steroids and other medication for chronic ailments should have regular eye examinations to monitor the status of the lens, eye pressure and to see if there are any secondary changes happening in the lens which will probably warrant an alteration in the treatment schedule.
4. Follow the schedule of medication prescribed by a physician, whatever the ailment, without under-dosing or over-dosing yourself.
5. Parents should exercise caution while purchasing toys for their children and avoid getting water guns, remote control toys with antennas sticking out and all other potentially dangerous items which could pose a threat to the eye.
6. Children and individuals, especially those wearing glasses, should use protective headgear while indulging in sports like cricket.

Is surgery then, the only treatment of cataract? The age at which cataract may begin to form, varies from person to person, depending upon various factors. Also, its progression is not predictable. Dr.Azim explains, “It can start as a few radiating fibres without impairing vision. People think having cataract implies immediate surgery. This is not so! We operate only if the vision is affected to such an extent that the person cannot carry on his normal, routine activities. A person with 80% cataract may actually not have any symptoms and the doctor just picks it up during a routine checkup! There are people in certain profession (jewelers, watch repairers, for example), who come to us early, complaining of impaired vision. The progression of cataract also depends on the profession. Such a person would require surgery to carry on with this work. Indication for surgery is not doctor-dependent but patient-dependent because the progression of the condition is not predictable.”


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