Cataract

What is a Cataract?

A cataract is a clouding of the lens of the eye. The lens is a clear disc within the eyeball. It is normally transparent and is situated behind the pupil. It focuses incoming light rays to form a sharp, distinct image onto the retina, similar to the way a camera lens focuses an image onto film.

A cataract is like a dirty or cloudy camera lens. It blocks light rays from entering the eye, thus blurring vision.

A cataract is neither a tumor nor an abnormal growth of tissue in the eye. It is due to degeneration in the contents of the lens, resulting in its clouding. It is easily detected with special instruments used by doctors.

What Causes A Cataract?

Cataracts can be categorized according to its underlying causes. The most common cause is due to ageing, known as a Senile Cataract, which usually affects adults over the age of 50.

Patients with diabetes mellitus are prone to cataracts. Diabetic Cataracts tend to cause fluctuating vision.

An eye injury may damage the lens resulting in Traumatic Cataracts.

Congenital Cataracts are present at birth. It is usually hereditary or caused by an infection that has affected the pregnant mother and unborn child.

Secondary Cataracts are cataracts caused by other diseases of the eye or body.

What Symptoms Are There?

The main symptom is blurred vision. Other symptoms include glare, poor vision in bright surroundings, seeing multiple images and the need for frequent spectacle prescription changes, which become increasingly unsatisfactory in terms of visual improvement.

What Treatment Is Available?

Treatment for a cataract is warranted when it affects a person’s lifestyle. Surgery is the only effective way to remove a cataract. Fortunately, cataract surgery is usually highly successful with more than 90% of patients regaining good vision. This high success rate is attributed to advances in surgical microscopes, wound suturing, effective prevention of infections and early mobilization. Most cataract surgeries are performed as day surgical procedures without the need for hospital admission.

Cataracts cannot be removed with medication. The decision for removal of the cataract should be made only after consultation with an eye specialist.

Vision may worsen several months after cataract surgery due to the thickening of the posterior capsule. Fortunately, this can be improved with an outpatient laser treatment known as a capsulotomy.

Phacoemulsification

This is a recent advancement in the technique of cataract surgery. Using ultrasonic power, the cataract can be removed through a smaller wound. Suturing is usually not required and restoration of vision is faster.

With the removal of the lens, an artificial lens is needed to substitute the function of the focusing light rays onto the retina. This can be achieved in the following ways:

A. Intraocular Lens Implants
These are artificial lenses placed in almost the same position as the natural lens of the eye. These are permanent implants which require no maintenance.

The latest advances in implants included folded lenses, multifocal lenses and accommodative lenses. For a small percentage of patients, vision may worsen many months or years after cataract surgery, due to a delay thickening of the capsule around the lens implant. Fortunately, this can be eliminated with a very simple outpatient laser treatment known as capsulotomy.

B. Foldable Intraocular Lens Implants
The latest advances in implant technology: these new implants can be folded and implanted into the eye through a small wound. The implants are then unfolded into their positions in the eyes. As these implants require only a small wound, it heals quickly and visual quality is excellent.

C. Spectacles

In the days before intraocular implants, thick glasses were used to focus the light rays onto the retina. However, the “owl-like” spectacles were thick and heavy, providing poor quality of vision. These glasses are unsuitable for patients who require cataract surgery in only one eye.

Today, spectacles are used only to correct mild residual power, if any, after the implantation of intraocular lenses. As these prescriptions are generally very mild, they are thinner and lighter and thus provide much better quality vision.

D. Contact Lenses

Contact lenses can be used in a similar way as spectacles. However, these require special care.

Remember:

Cataracts are the most common cause of poor vision in the elderly. It is a curable form of blindness. Do not ignore any emerging symptoms. Have regular check-ups with an eye specialist. Early detection can prevent permanent blindness.

 

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