INTRODUCTION

A cataract is a dense, cloudy area that forms in the lens of the eye. A cataract begins when proteins in the eye form clumps that prevent the lens from sending clear images to the retina. The retina works by converting the light that comes through the lens into signals. It sends the signals to the optic nerve, which carries them to the brain.

It develops slowly and eventually interferes with your vision. You might end up with cataracts in both eyes, but they usually don’t form at the same time. Cataracts are common in older people.

SYMPTOMS OF CATARACTS

Common symptoms of cataracts include:

• blurry vision
• trouble seeing at night
• seeing colors as faded
• increased sensitivity to glare
• halos surrounding lights
• double vision in the affected eye
• a need for frequent changes in prescription glasses

WHAT CAUSES CATARACTS?

There are several underlying causes of cataracts. These include:

• an overproduction of oxidants, which are oxygen molecules that have been chemically altered due to normal daily life
• smoking
• ultraviolet radiation
• the long-term use of steroids and other medications
• certain diseases, such as diabetes
• trauma
• radiation therapy

TYPES OF CATARACTS

There are different types of cataracts. They’re classified based on where and how they develop in your eye.

· Nuclear cataracts form in the middle of the lens and cause the nucleus, or the center, to become yellow or brown. A nuclear cataract may at first cause more nearsightedness or even a temporary improvement in your reading vision. But with time, the lens gradually turns more densely yellow and further clouds your vision. As the cataract slowly progresses, the lens may even turn brown. Advanced yellowing or browning of the lens can lead to difficulty distinguishing between shades of color.

· Cortical cataracts are wedge-shaped and form around the edges of the nucleus. A cortical cataract begins as whitish, wedge-shaped opacities or streaks on the outer edge of the lens cortex. As it slowly progresses, the streaks extend to the center and interfere with light passing through the center of the lens.

· Posterior capsular cataracts form faster than the other two types and affect the back of the lens. A posterior subcapsular cataract starts as a small, opaque area that usually forms near the back of the lens, right in the path of light. A posterior subcapsular cataract often interferes with your reading vision, reduces your vision in bright light, and causes glare or halos around lights at night. These types of cataracts tend to progress faster than other types do.

· Congenital cataracts, which are present at birth or form during a baby’s first year, are less common than age-related cataracts. Some people are born with cataracts or develop them during childhood. These cataracts may be genetic, or associated with an intrauterine infection or trauma. These cataracts also may be due to certain conditions, such as myotonic dystrophy, galactosemia, neurofibromatosis type 2 or rubella. Congenital cataracts don't always affect vision, but if they do they're usually removed soon after detection.

· Secondary cataracts are caused by disease or medications. Diseases that are linked with the development of cataracts include glaucoma and diabetes. The use of the steroid prednisone and other medications can sometimes lead to cataracts.

· Traumatic cataracts develop after an injury to the eye, but it can take several years for this to happen.

· Radiation cataracts can form after a person undergoes radiation treatment for cancer.

RISK FACTORS OF CATARACTS

Risk factors associated with cataracts include:

• older age
• heavy alcohol use
• smoking
• obesity
• high blood pressure
• previous eye injuries
• a family history of cataracts
• too much sun exposure
• diabetes
• exposure to radiation from X-rays and cancer treatments

PREVENTIONS

· Have regular eye examinations. Eye examinations can help detect cataracts and other eye problems at their earliest stages. Ask your doctor how often you should have an eye examination.

• Quit smoking. Ask your doctor for suggestions about how to stop smoking. Medications, counseling and other strategies are available to help you.
• Manage other health problems. Follow your treatment plan if you have diabetes or other medical conditions that can increase your risk of cataracts.
• Choose a healthy diet that includes plenty of fruits and vegetables. Adding a variety of colorful fruits and vegetables to your diet ensures that you're getting many vitamins and nutrients. Fruits and vegetables have many antioxidants, which help maintain the health of your eyes.

Studies haven't proved that antioxidants in pill form can prevent cataracts. But, a large population study recently showed that a healthy diet rich in vitamins and minerals was associated with a reduced risk of developing cataracts. Fruits and vegetables have many proven health benefits and are a safe way to increase the amount of minerals and vitamins in your diet.

• Wear sunglasses. Ultraviolet light from the sun may contribute to the development of cataracts. Wear sunglasses that block ultraviolet B (UVB) rays when you're outdoors.
• Reduce alcohol use. Excessive alcohol use can increase the risk of cataracts.

SURGERY

Surgery is recommended when cataracts prevent you from going about your daily activities, such as reading or driving. It’s also performed when cataracts interfere with the treatment of other eye problems.

One surgical method, known as phacoemulsification, involves the use of ultrasound waves to break the lens apart and remove the pieces.

Extracapsular surgery involves removing the cloudy part of the lens through a long incision in the cornea. After surgery, an artificial intraocular lens is placed where the natural lens was.

Surgery to remove a cataract is generally very safe and has a high success rate. Most people can go home the same day as their surgery.