A shift in focus

A shift in focus
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First Published: Tue, Feb 20 2007. 12 21 AM IST
Updated: Tue, Feb 20 2007. 12 21 AM IST
As the 40th birthday approaches, the fine print starts blurring and the arm that is holding the newspaper needs to stretch further and further away.
Presbyopia, which means ageing eye in Greek, hits most people in the 40-50 age group, where the lens loses its ability to focus, making reading and near vision tasks like working on the computer difficult.
Till recently, presbyopia could only be corrected by wearing reading glasses or contact lenses. Or, for those with existing myopia, by wearing bifocal lenses. In some cases, even trifocal lenses are recommended with different adjustments for reading, far distance vision and the intermediate zone, which has cropped up because people now spend more time at their computers.
Globally, doctors have been experimenting on different procedures, including surgical ones, to treat presbyopia. In India, too, the action on this front is hotting up.
Vadodara-based Dr Rupal Shah is palpably excited. For the last two months, she has been taking on very selective cases of presbyopia, using a laser-based technique they claim has so far been used only in Germany and France. “We are essentially increasing the depth of focus of the lens with this technique,” says Shah, who says it is still too early to talk about their trials. “In 3-4 months, we are confident we will be able to take on presbyoptic cases,” she says.
So far, eye surgeons in India have been using a technique called monovision to combat presbyopia. This is performed on patients with an existing myopic condition.
In monovision, the eye surgeon leaves some minus vision behind in one eye so that as presbyopia sets in there is some natural adjustment. The brain gradually adapts to using one eye for certain tasks depending on the distance.
However, this procedure is not approved of by everyone. “I am not doing it,” says Dr Mahipal Sachdev of the Centre of Sight, Delhi, categorically. He bluntly points out that this option is only for those “who are not exacting”. Even Shah, who had been doing monovision till recently, points out the drawbacks. “You have to carry out extensive counselling with the patient,” she says.
There are other non-laser treatments like CK (Conductive Keratoplasty), a minimally invasive procedure developed specifically for presbyopic patients. Here there is controlled release of radio frequency energy to strengthen the cornea. But the aim is the same as in monovision—correct one eye and leave it to the brain to make adjustments.
Research and trials on presbyoptic Lasik, “which makes the cornea zonal” is what several companies are currently involved with—and probably what the Shahs in Vadodara are doing. “There are several laser companies that have released software for this,” says Sachdev. Essentially, it works on the lens to adapt to various types of vision requirement—the central portion is for distant vision and so on. In the US, this procedure is awaiting FDA approval.
For his part, Sachdev recommends lens based refractive surgery where a multifocal lens is implanted. This procedure is akin to lens replacement for cataracts in which the natural lens is surgically removed and a synthetic lens inserted. The artificial lens is connected to muscle fibres that are responsible for moving and focusing the original lens. But the costs for this are huge—Rs55,000 for one eye!
Meanwhile, as the medical world tries to find the best treatment for presbyopia, there is a tremendous merging or overlapping of techniques. Keep your eyes peeled.
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First Published: Tue, Feb 20 2007. 12 21 AM IST
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