Dr. Tariq Jagnarine
Family Medicine,
Endocrinology
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.
A cataract develops slowly, and eventually interferes with one’s vision. Persons might end up with cataracts in both eyes, but they usually don’t form at the same time. Cataracts are common in older people. More than half of the people in the United States have cataracts, or have undergone cataract surgery by the time they’re 80 years old, according to the National Eye Institute.
Causes of cataracts
There are several underlying causes of cataracts. These include:
* 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 centre, to become yellow or brown.
* Cortical cataracts are wedge-shaped, and form around the edges of the nucleus.
* Posterior capsular cataracts form faster than the other two types, and affect the back of the lens.
* Congenital cataracts, which are present at birth or form during a baby’s first year, are less common than age-related cataracts.
* Secondary cataracts are caused by diseases 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 has undergone 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
Symptoms of cataracts
Common symptoms of cataracts include:
* Blurry vision
* Trouble seeing at night
* Seeing colours as faded
* Increased sensitivity to glare
* Halos surrounding lights
* Double vision in the affected eye
* A need for frequent changes in prescription glasses
Diagnosing cataracts
The doctors will perform a comprehensive eye exam to check for cataracts and to assess one’s vision. This would include an eye chart test to check your vision at different distances, and tonometry to measure your eye pressure. The most common tonometry test uses a painless puff of air to flatten the cornea and test the eye pressure. Doctors would also put drops in the eyes to make the pupils bigger. This makes it easier to check the optic nerve and retina at the back of the eye for damage.
Other tests doctors might perform include checking a person’s sensitivity to glare and the perception of colours.
Treatment of cataracts
If a person is unable or uninterested in surgery, their doctor may be able to help them manage their symptoms. They may suggest stronger eyeglasses, magnifying lenses, or sunglasses with an anti-glare coating.
* Surgery
Surgery is recommended when cataracts prevent persons from going about their daily activities, such as reading or driving. A surgery is 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. Some of the risks of cataract surgery include infection, bleeding, and retinal detachment, though incidents of all those complications are less than 1%. Most people can go home on the same day that they had surgery.
Cataracts can interfere with daily activities, and lead to blindness when left untreated. Although some stop growing, they don’t get smaller on their own. The surgical removal of cataracts is a very common procedure, and is highly effective roughly 90 percent of the time, according to the National Eye Institute.
<<Prevention of cataracts>>
To reduce your risk of developing cataracts:
* Protect your eyes from UVB rays by wearing sunglasses outside
* Have regular eye exams
* Stop smoking
* Eat fruits and vegetables that contain antioxidants
* Maintain a healthy weight
* Keep diabetes and other medical conditions in check.
