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Cataract

About Cataract

What is Cataract?

Normally, the lens of the eye is clear and allows light rays to pass through easily. When cataract develops, the lens becomes cloudy and opaque. The light rays no longer pass through the lens easily, so the patient cannot see clearly. Cataract is not a new growth or a film over the eye. It is not contagious.

Reasons for Cataract

  • It usually occurs in patients above the age of 50.
  • Cataracts in children are rare. Eye injuries may cause cataracts in patients of any age.
  • Diseases like glaucoma, iritis, eye tumours, and diabetes may cause cataracts.
  • Prolonged treatment with steroid drugs, either for local (e.g, allergic conjunctivitis) or systemic diseases (e.g., asthma) may lead to cataract formation.

Types of Cataract

There are many types of cataracts
A change in the chemical composition of the lens causes most cataracts. The following are the various types of cataracts.
  • Senile Cataract
    This is the most common type of cataract, comprising 80 percent of the total cataracts. It occurs in patients above the age of 50.
  • Congenital Cataract
    Cataracts in children are rare. They can be caused by infection of the mother during pregnancy, or they may be hereditary.
  • Traumatic Cataract
    Eye injuries may cause cataracts in patients of any age.
  • Secondary Cataract
    Eye diseases, like glaucoma, iritis, eye tumours, and diabetes may cause cataracts.
  • Drug-induced Cataract
    Prolonged treatment with steroid drugs, either for local (e.g., allergic conjunctivitis) or systemic diseases (e.g., asthma) may lead to cataract formation.

Symptoms

cataractpic

Cataract formation is not associated with "signals" such as pain, redness or tearing.
The common symptoms are:

  • Blurring or dimness of vision
  • Double vision
  • Glare & sensitivity to light
  • Yellowing of colours

Treatment

Cataract cannot be cured by medicines or spectacles. Removal of the clouded lens by surgery is the only treatment.

Types of Cataract Removal:
Routine method (Old method)

After administering a local anaesthesia, a 10 mm incision is made in the eye. The cataract lens is removed and it may be replaced by an Aphakic glass. The incision is then closed with sutures. After the surgery, glasses with high power called ophakic spectacles are prescribed to the operated person.

Disadvantages:

These ophakic glasses are heavy, images seen are larger than they normally appear to be, and the field of vision is restricted.

New method with implanting of Intraocular lens (IOL) with sutures:

After administering a local anaesthesia, a 10 mm incision is made in the eye. The clouded lens is removed and replaced by an IOL and the incision is then closed with sutures. The entire procedure takes only 15 minutes.

What is IOL?

  • Intra Ocular lens (IOL) is a tiny transparent convex lens.
  • It is made of polymethyl methacrylate , (a harmless plastic substance).
  • Unlike contact lens, an IOL stays permanently in the eye and does not cause irritation.

Advantages of IOL:

Since the lens is placed inside the eye, most often the patient need not wear glasses for clear vision. But sometimes patient has to wear glasses for clarity.

  • Images are clear and of the same dimension without distortion
  • Full vision returns very clearly
  • Normal field of vision
Phaco or sutureless surgery with implantation of IOL

After giving a local anaesthesia, a 5mm incision is made in the eye. The cataract lens is broken into small pieces by a machine with ultrasonic waves and removed with a needle. A specially prepared IOL is inserted into the eye and the wound heals without sutures. Unlike contact lenses, an IOL stays permanently in the eye and does not cause irritation. Since the artificial lens is placed inside the eye, images are clear without distortion. Full vision returns very early with normal field of vision.

Advantages of Phaco

  • Early surgery can be done, so that patient need not wait for the cataract to mature
  • Small Incision
  • No sutures and no need of suture removal.
  • No irritation, no watering
  • Early return to work
  • No need to continue drops for a long time
  • No need for hospital stay, Even if the patient stays, it is only for a short time
  • Only one post-operative visit
  • Stable refraction after one month

The ophthalmic surgeon decides whether the patient can undergo phaco or not.

Source: Aravind Eye Care

Cataract- Myths & Facts

MYTH - Cataracts “grow” on top of the eye

FACT : Cataracts are a clouding of the eye’s lens, and the lens is within the eye, not on its surface. The eye’s natural lens is made up of water and protein fibres that are arranged in a way that makes the lens clear and allows light to pass through. As you age, the protein fibres begin to clump together and cloud small areas of the lens. Over time the clumping in one particular area will stand out, making it harder to see.

MYTH - Cataracts can be removed with lasers

FACT : Along with the misconception that cataracts grow on the surface of the eye, many people believe they can be removed with lasers. However this is not the case, because the clouding develops within the actual properties of the lens. In cataract surgery, your natural lens is broken up and removed with an instrument called a phaco probe. The natural lens is then replaced with an artificial lens within the eye called an IOL.

MYTH - Cataracts “grow back”

FACT : Not so. However, occasionally a cataract patient can develop a different, secondary cataract in the years or months following surgery. This happens when the membrane that holds the new lens implant becomes cloudy, increasing problems with glare and making it harder to see. This can be treated with laser surgery. It is a simple procedure in which your eye surgeon makes a small opening within the membrane to allow light to enter the lens. The procedure is quick and painless, takes less than fifteen minutes and is usually conducted in your doctor’s office

MYTH - A cataract must be “ripe” before it can be removed

FACT : In the past this was true – a cataract had to be in the advanced stage before it could be removed. However with modern cataract surgery, a cataract does not have to “ripen” to be removed. You can have a cataract removed as soon as it begins to affect your vision and quality of life.

MYTH - Only older people develop cataracts

FACT : Cataracts are most common among people over 65 years of age; however, cataracts can occur in people who are younger. These cataracts result from conditions such as diabetes, certain medications and other eye problems. In some cases cataracts can be present at birth; these are called congenital cataracts. For more information on the different types of cataracts, see Cataracts 101: Types and Causes.

MYTH - Cataract surgery is dangerous

FACT : Cataract surgery is one of the safest and most highly perfected surgical procedures in medicine, with a 95 per cent success rate. However, as with any surgery, risks do exist and should be discussed with your doctor before undergoing the procedure.

MYTH - It can take months to recover from cataract surgery

FACT : In many cases cataract patients notice a change in their vision immediately following surgery; however, some people will continue to improve in vision for a few months after that. You will not be able to bend or lift anything heavy for up to three weeks after your procedure and you will need to avoid rubbing or pressing your eye. Other than that, you should be able to resume normal activities the day after surgery, which is when the patch over your eye is removed. (Read Olivette Shaw’s story to learn more about cataract surgery.)

MYTH - There is no need for glasses after cataract surgery

FACT : Whether or not glasses are needed following surgery depends on the type of intraocular lens implanted. With a monofocal lens, patients will most likely still need glasses for near and intermediate distances to read or work on the computer. Many people choose to have a multifocal lens implanted since in most cases all distances are corrected and glasses may not be necessary. You may want to talk to your doctor about whether multifocal lenses might be good for you. Read more information on lens options for cataract surgery.

MYTH - Cataracts can spread from one eye to the other

FACT : Cataracts can develop in one eye or both of them, but they do not spread

MYTH - Cataracts are made worse by close-up tasks such as reading and sewing

FACT : You can’t develop a cataract, or make an existing cataract worse, by doing these tasks. The causes of cataracts are not related to how you use your eyes. However, it is likely that you will notice a cataract because of close-up tasks, since one of the signs of cataracts is requiring a lot more light to do these activities.

MYTH - There are ways to reverse cataracts once they occur

FACT : The clouding of the lens is a natural part of the aging process and cannot be avoided. However, you can make lifestyle adjustments to slow or prevent the development of cataracts:

  • If you smoke, consider quitting.
  • Eat a balanced diet, including a lot of fruits and vegetables.
  • Wear sunglasses (with 100% UV A and B protection) and avoid excessive sun exposure.

Related resources

  1. WHO resources on Cataract
  2. LVPEI

     



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