When we look at any object, light rays pass from the object through the transparent cornea and the clear lens to strike the retina and form an image. The retina then relays the image to the brain through a set of wires called as optic nerve.
What is Cataract?
For normal vision, it is imperative that the lens of the eye is clear and transparent, so that light rays can pass through it. When the lens becomes cloudy or opaque, light rays are not easily transmitted to the retina. This opaque lens is called as cataract. Cataract usually develops gradually over a long period and may affect both eyes in different degrees.
WHAT CAUSES CATARACT?
Aging is the most common cause. As one ages, the proteins in the lens break down making it rigid and cloudy. Other than aging, many conditions can accelerate the break-down of the lens proteins like
- Eye Injury or Prolonged exposure to radiation, sun or x-rays
- Inflammation of your iris, uvea etc.
- Disorders like hypothyroidism and atopic dermatitis
- Genetic diseases like Down’s, Wilson’s, Homocystinuria, Myotonic Dystrophy etc.
- Infections affecting the baby in its womb like Herpes, Rubella, Syphilis, etc.
- Medications like steroids and haloperidol
WHAT ARE THE SYMPTOMS?
Cataract develops very gradually and painlessly. It may affect one or both eyes.
- Blurry Vision as if looking through a frosted glass
- Halos around objects especially bright lights e.g. excess glaring from oncoming headlights
- Loss of contrast sensitivity and dull appearance of colours
- Second Sight: Temporary improvement in near vision
- Frequent change of spectacle power
- Fading or yellowing of colors
- Poor night vision
- Double vision
- Need for brighter light
Treatment of Cataract
Surgery alone is the treatment of cataract. No medicines or diet can reverse cataract formation. During the surgery the cataractous lens is removed and is replaced by an artificial intra ocular lens (IOL).
Phacoemulsifi cation is the most advanced and accepted form of surgery. During this surgery, a very small opening of approximately 3mm is made in the eye and the cataract is removed by breaking it into small pieces, which are then gently sucked out with the same instrument. The incision taken is so small that it requires no stitches and heals rapidly. The makes it possible for the patient to resume normal activities early.
Once the cataractous lens is removed a new lens (IOL) is inserted in the same place.
There are a variety of IOLs which a patient can opt for. Typically there is a choice between foldable soft IOLs and non foldable hard IOL. Lenses could be either of PMMA, Silicone or Acrylic material. One can opt between monofocal lens and multifocal lens.
With monofocal IOL, the distance vision is clear without glasses but one has to wear reading classes. With multifocal IOL, vision is good both for distance and near and one is almost independent of glasses. However for very fine prints glasses may still be needed.
Toric IOLs are now available for patients with high cylindrical numbers. (Please discuss with your doctor the type of lens best suited for you).
Cataract surgery is done under local anaesthesia. The new technique of eye drop anaesthesia (no injection) has distinct advantages over the conventional technique of giving injection anaesthesia.
In certain circumstances, the alternative technique of extra capsular cataract surgery with injection anaesthesia may need to be adapted as felt necessary for the best interest of the patient. Cataract surgery has very predictable results with a success rate of over 95%.
Bladeless Cataract Surgery
The latest technique known as bladeless cataract surgery which has no injection, no stitch and no patch had made the surgery very easy for the patient, though it is more demanding on the surgical skills of your doctor. In some people, the natural capsule that supports the IOL may become cloudy, several months after the surgery. If vision is affected, then laser can be used to open this capsule in a couple of minutes.