What is the lens?

Think of the lens as a small cellophane bag filled with clear protein located in the front part of the eye.
It has two main functions. Because it is clear, it allows the passage of light coming into the eye to the retina (except for some ultraviolet light), and its curved shape focuses the rays on the retina for clear vision. It is also able to change its shape to focus on near objects.

What can go wrong with the lens?

As we grow older, the lens proteins lose their clarity and elasticity. Thus, less light passes into the eye and we are unable to see clearly – this change is what we call a cataract. As the lens becomes more rigid it is not able to change shape and hence we are unable to see near objects (presbyopia).

How will I know if I have a cataract?

A gradual loss of clear vision is the main symptom of a cataract. Vision – for distance or near or for both may be blurred, objects may have fuzzy edges, lights at night may have colored haloes, and there can be changes in color perception. Sometimes, doubling of images may occur. Depending on the type of cataract, some of these changes are worse at night, some in daytime, and some – all the time. Cataractous changes in the lens often progress gradually, and are painless.

What are common causes of cataract?

Apart from ageing, a number of other factors can influence cataract formation – injuries, inflammation in the eye, other eye diseases, diabetes, use of some medications, and so on. Sometimes, they are genetic and can be seen at birth. There is unfortunately no proven treatment to prevent or slow the progression of age-related cataract.

How can a cataract be treated?

At present the definitive treatment for a cataract remains surgery. The surgeon will remove the opaque lens through a very small opening in the eye wall in a fast, painless manner. The small opening made closes on it own without any need for stitches. The operation can be done either using anesthetic eye drops or an injection to anesthetize the eye. A foldable lens (intraocular lens or IOL) is inserted through the small opening. The new lens inside the eye allows a greatly improved quality of vision and minimizes the need for glasses.

Recent advances in cataract surgery?

With current technology, cataracts can be removed with a high degree of success and safety. There are a number of choices for IOLs. Yellow-tinted IOLs reduce the entry of blue light into the eye – as this may be harmful to the retina. Toric IOLs allow excellent unaided vision in people with corneal astigmatism. Prior to the availability of these lenses, such patients needed ancillary surgical procedures or glasses after surgery for clear vision. Multifocal IOLs try to reduce the need for reading glasses after surgery. Aspheric IOLs improve the contrast and quality of night vision. It is best to discuss with your doctor about the appropriate choice of lens for your eye.

Can cataract recur after surgery?

No. However, in order to support the IOL inside the eye, the surgeon has to retain a part of the natural lens – called the posterior capsule. This membrane may sometimes increase in thickness or lose clarity after surgery. This may sometimes cause blurred vision many months to years after the cataract operation. If a patient experiences significant difficulty due to this a simple laser procedure (done in the consultation room itself) clears the membrane to quickly restore clear vision.

General health information

Although cataracts are often due to ageing, exposure to ultraviolet light may hasten these changes. Wear the right type of dark glasses when you are outdoors in bright sunlight. This will reduce ultraviolet light exposure and may help protect your eyes. Good control of diabetes also helps to reduce the rate of progression of cataract. And stop smoking – that helps as well!