Cataract

By Faozat Aragbaye
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Cataract is a clouding of the lens in the eye due to protein buildup in the body, which leads to reduced vision and loss of sight if left untreated.

TYPES OF CATARACT

There are three primary types of cataracts:

• Nuclear sclerotic cataract- most common type of cataract. It forms deep in the central zone (nucleus). Nuclear cataracts are usually associated with aging. It progresses slowly and may take several years of gradual development before it begins to affect vision.
• Cortical cataract- cortical cataract forms in the cortex of the lens and gradually extends from the outside of the lens to the centre in a spoke-like fashion People with diabetes are at risk for developing cortical cataracts.
• Posterior subcapsular- cataract-occurs at the back of the lens. People with diabetes or those taking high doses of steroid medications have greater risk of developing a subcapsular cataract.
• Secondary cataract: cataracts can form after surgery for other eye problems.
• Traumatic cataract: cataract can develop after an eye injury, sometimes years later.
• Congenital cataract: some babies are born with cataracts or develop them in childhood, often in both eyes.
• Radiation cataract: cataracts can develop after exposure to some types of radiation.

CAUSES

The lens is mostly made of water and protein. The protein is arranged in a precise way that keeps the lens clear and lets light pass through it.

But as we age, some of the protein may clump together and start to cloud a small area of lens. This is a cataract, and over time, it may grow larger and cloud more space, making it harder to see. The cause for the changes in the eye’s lens with age is unknown.

One theory of cataract formation is that many cataracts are caused by oxidative changes in the human lens.

RISK FACTORS

Besides advancing age, Cataract risk factors include:

• Ultraviolet radiation
• Diabetes
• Hypertension
• Obesity
• Smoking
• Prolonged use corticosteroid medications
• Statin medicines used to reduce cholesterol
• Previous eye injury or inflammation
• Previous eye surgery
• Hormone replacement therapy
• Significant alcohol consumption
• High myopia
• Family history

SYMPTOMS AND SIGNS

Cataracts are not painful. The symptoms include:

• Cloudy or blurry vision
• Poor night vision
• Glare. Headlights, lamps, or sunlight may appear too bright. A halo may appear around lights.
• Frequent prescription changes in eyeglasses
• Reduces ability to identify colours
• Double vision or multiple images

DIAGNOSIS

Cataract is detected through a comprehensive eye examination that includes:

• Visual acuity test- eye chart measuring distances of vision
• Dilated eye examination
• Tonometry.

TREATMENT

The symptoms of early cataract may be improved with new eyeglasses, brighter lighting, anti-glare glasses, or magnifying lenses. If these measures do not help, surgery is the only effective treatment.

Surgery involves removing the cloudy lens and replacing it with an artificial lens. A cataract needs to be removed only when vision loss interferes with everyday activities such as walking, driving, reading or watching TV.

For some people, other eye problems prohibit the use of an artificial lens. In these situations, once the cataract is removed, vision may be corrected with eyeglasses or contact lenses.

Cataract surgery is generally safe, but it carries a risk of infection and bleeding. Cataract surgery increases the risk of retinal detachment.

PREVENTION

No studies have proved how to prevent cataracts or slow the progression of cataracts. But doctors think several strategies may be helpful including:

• Regular eye examinations – eye examinations can help detect cataracts and other eye problems at the earliest stages.
• Wear sunglasses- ultraviolet lights from the sun may contribute to the development of cataracts. Wear sunglasses that block ultraviolet B(UVB) rays when outdoors
• Manage other health problems – follow your treatment plans for diabetes and other medical conditions that can increase the risk of developing cataracts
• Reduce alcohol use- excessive alcohol use can increase the risk of cataracts
• Quit smoking- smoking also increases risk of developing cataracts.
• Choose a healthy diet that includes plenty of fruits and vegetables.