A cataract is an eye condition that is characterized by the clouding of the lens inside the eye. Cataracts usually reduce the vision intensity of the eye and its one of the most common causes of blindness. Cataracts are usually associated with old age though other underlying factors have contributed to the condition. People with cataracts often experience difficulties in differentiating between different types of colors, reading, driving and recognizing faces.
Types of Cataracts
The type of cataracts depend on the cause as well as the part affected. The following are the most common types of cataracts.
-Nuclear Sclerosis cataracts are the most common type of cataracts. They affect the central/nuclear part of the lens. They’re associated with poor distance vision.
-Posterior subcapsular cataracts affect the back part of the lens where the capsule is found. These types of cataracts highly affect daylight vision since much of the light is focused at the back of the lens.
-Cortical cataracts are associated with the opaque nature of the cortex. They’re caused by the water changes in the periphery part of the lens. The cataracts are associated with light scatter during the night.
-Congenital cataracts occur during childhood or babies are affected from birth. This may be due to the mother contracting an infection during pregnancy.
Causes of Cataracts
Age is one of the most common causes of the condition. This can be attributed to the fact that, as one gets old, the protein content that makes up the lens of the eye happens to get denatured. Denaturing of this protein layer exposes the eye to toxins and ultraviolet rays which in turn can destroy the lens causing cataracts. Blunt and sharp (severe) traumas are the leading causes of accidental cataracts.
A blunt trauma leads to the thickening, swelling and whitening of the lens fibers. Medication can reduce the swelling but the injured fibers of the lens remain and form a whitish cloud.
Severe trauma on the other hand leads to the destruction of the capsule that holds the lens. As a result of the injury, water from other parts of the eye may penetrate the capsule leading to the swelling and eventually whitening which obstructs view.
Strong UV lights penetrate the protective layer of the lens leading to cataracts. Electric rays also denature the protein leading to cataracts. These types of cataracts are common with furnace workers and glassblowers.
Skin diseases such as eczema and atopic dermatitis have been found to cause shield ulcers cataracts while ichthyosis has been found to cause cuneiform cataracts.
Cigarette smoking and drug use have been found to increase the rate of getting cataracts by two fold. Posterior subcapsular cataracts are the most common types of cataracts associated with smoking. Medications such as corticosteroids have been found to induce cataracts in people suffering from schizophrenia.
Cataracts are treated successfully by surgery. As Dr. Mahootchi of The Eye Clinic of Florida explains, the surgery involves the removal of the clouded lens and replacing it with a clear artificial lens. The most commonly used cataract surgery is phacoemulsification. It involves the use of ultrasonic energy to emulsify the affected lens.
Another form of surgery is the extracapsular cataract extraction (ECE). It involves the manual removal of the lens while leaving a small part of the capsule intact. It’s useful when dealing with hard cataracts that cannot be removed using phacoemulsification.
The other type of surgery though rarely used due to post-operative complications is the intracapsular cataract extraction (ICE). It involves the removal of the lens and the surrounding capsules through large incision.