Both are typically age-related eye problems. But macular degeneration does not cause cataracts; nor does a cataract cause macular degeneration.
A cataract is clouding of the crystalline lens inside the eye. The lens is located directly behind the pupil and iris (the colored part of the eye) and is about the size and shape of an M&M candy. Along with the clear front surface of the eye (cornea) the lens focuses light onto the retina, the inner lining of the back of the eye, to initiate the process of vision.
Cataract formation appears to be associated oxidation of proteins in the lens, which disrupts the orderly structure of components within the normally clear lens and causes the lens to become opaque. The underlying cause for these lens changes is unknown, but poor nutrition, overexposure to UV rays from sunlight, excessive alcohol consumption and cigarette smoking have been identified as risk factors.
Cataracts and macular degeneration (AMD) both are serious eye conditions that can cause loss of vision. But unlike the permanent vision loss caused by AMD, vision loss from cataracts usually can be restored with cataract surgery.
The risk for cataracts, like the risk for AMD, increases with age. But cataracts also can occur in young people, especially those with diabetes or a history of prolonged use of steroid medications. Also, some cataracts, called traumatic cataracts, can occur after an injury to the eyes or head. Other cataracts, called congenital cataracts, can be present at birth or occur shortly thereafter.
Most cataracts are detected during an eye exam, often before they cause significant vision problems. Symptoms of cataracts include blurred vision, glare and halos around lights (especially when driving at night), and color vision disturbances. Like macular degeneration, cataracts are painless.
Because modern cataract eye surgery is so safe and effective, many people no longer wait for their vision to be significantly blurred before having surgery. The procedure takes only a few minutes and is performed on an outpatient basis.
A cataract operation is a two-step procedure: First, the surgeon uses an ultrasonic device to break up the cloudy lens into small pieces in a process called phacoemulsification, which enables cataract removal through a relatively small incision in the eye. The surgeon then implants a clear intraocular lens (IOL) in the eye to replace the natural lens.
Measurements are taken prior to surgery to help the surgeon choose the proper IOL power so little or no nearsightedness, farsightedness or astigmatism remains after surgery.
During a routine comprehensive eye exam, your optometrist or ophthalmologist will dilate your pupil to enable him or her to check the entire lens of your eye for cataracts. If a cataract is present, your general eye doctor usually will monitor your vision for a period of time with regularly scheduled exams, and advise you regarding when it may be time to consider cataract surgery.