“My kitchen curtains really are white! I thought they were dirty and yellow and I’ve been washing them every week for the last year trying to get them clean.” This is a typical comment of a patient who has just had the cataracts removed from their eyes. For those who could not see well enough to get a driver’s license renewed, cataract removal is a necessity. For those who were almost blind, it seems like a miracle.
The colored ring of muscle fibers in the human eye, called the iris, opens and closes to admit more or less light. In the middle of the iris is a dark circle, which is really a hole, called the pupil. Behind this light hole is the lens of the eye. This lens is a bag or envelope of clear, gelatinous protein that becomes fatter or thinner to focus the light on the back of the eye. When the lens becomes cloudy, discolored to grey or yellow, and will not admit sufficient light, it is called a cataract.
There are many causes of cataracts: long-term steroid use (including hormones), penetrating eye injury, and diabetes. However, the most common cause is aging made worse by long exposure to the UV rays of sunlight. This makes cataracts even more common in areas where there is more direct sunlight, such as the southern United States. Half of people over seventy-five years of age have some degree of cataracts affecting their vision.
Fortunately, modern surgical techniques can remove the cataract and replace it with an artificial lens. After giving the patient some relaxing medicine and placing a few drops of local anesthetic in the eye, the surgeon is able to make a very small, painless incision just outside the colored part of the eye. A small instrument is placed in the eye that emits ultrasound waves to break the cloudy lens into small pieces. Another instrument suctions out these pieces, leaving the envelope of the lens intact. A small tube is inserted which has the new lens rolled up inside of it. The artificial lens is pushed out into the envelope where it unfolds and fills the center part of the envelope, being held in place by two small wire arms. This miracle of surgery usually happens in about ten to fifteen minutes.
Over one million cataract surgeries are performed in the United States every year, making it the most common surgery. The results are usually spectacular. Those who could only see fuzzy grey forms or no forms at all, now see perfectly clear images. Those who thought the world had taken on a dull brown or yellow tinge now find the world has sharp, clear, brilliant color again.
The complication rate for the surgery is less than one percent, and consists mainly of developing cloudiness in the old lens envelope. This can be cleared up with a one-time laser treatment in the doctor’s office. Other, more serious complications such as retinal detachment are rare. To watch for these complications, both eyes are seldom done at the same time.
Is the new vision of the patient perfect? No. The artificial lens cannot get fatter or thinner and change its focal length. Therefore, near vision must be assisted by reading glasses. In high intensity light areas (such as the southern US), sunglasses should be used because the UV light can age the artificial lens. But for those who have lost their vision – and their driver’s license – cataract surgery can seem nothing short of miraculous.