A cataract is a dense, cloudy area that forms in the lens of the eye.
The lens is a clear disc-like structure that helps to focus light on the retina. It can do this because it is adjustable, and uses a muscle called the ciliary muscle to change shape and help us focus on objects at different distances. The automatic focusing of the lens is a reflex response and is not controlled by the brain.
A cataract begins when proteins in the lens 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 electrical signals. It sends these signals to the optic nerve, which carries them to the brain.
It develops slowly and eventually interferes with your vision. 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.
• 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 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 cancer treatments
Diagnosing Cataracts
Your doctor will perform a comprehensive eye exam to check for cataracts and to assess your vision. This will include an eye chart test to check your vision at different distances and tonometry to measure your eye pressure.
Your doctor will also put drops in your eyes to make your pupils bigger. This makes it easier to check the optic nerve and retina at the back of your eye for damage.
Other tests your doctor might perform include checking your sensitivity to glare and your perception of colors.
Treatment of Cataracts
If you’re unable or uninterested in surgery, your doctor may be able to help you manage your symptoms. He might suggest stronger eyeglasses, magnifying lenses, or sunglasses with an anti-glare coating. But those will not stop the development of the cataract or give you back your vision before the onset of the cataract.
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.
The most modern surgical method, known as femtosecond laser assisted phacoemulsification, involves the use of a laser to break up the opacified lens and remove the pieces with a special ultrasound instrument.
After surgery, an artificial intraocular lens is placed where the natural lens was.
Surgery to remove a cataract is very safe and has a high success rate. Some of the risks of cataract surgery include infection, bleeding, retinal detachment, though incidences of all those complications are far below 0.1%.
Outlook of a Cataract
Cataracts can interfere with daily activities and lead to blindness when left untreated.
The surgical removal of cataracts is a very common, safe procedure and is highly effective.
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