story by“Eyes really are amazing things. They fascinated me in medical school,” says Dr. Judianne Kellaway, clinical associate professor of Ophthalmology and Visual Science at The University of Texas Medical School at Houston. “Eyes show our feelings and are the most important way we gather information about our world.”
Yet as amazing as the eyes are, they age like all the other parts of the body. That aging process causes changes in our vision, and some conditions are more prevalent in women.
Out of the 20.5 million Americans age 40 and older with a cataract, 12.7 million are women, and no one really knows why.
Another condition that can affect women early in a pregnancy is light sensitivity, but it usually subsides in the second trimester. Dry irritated eyes can also be a problem throughout pregnancy. The next time it reappears is during post-menopause. If the woman is 40 to 50 years old, it can be accompanied by presbyopia syndrome, which affects men and women and usually means glasses are needed for close-up work.
The eye is a hollow globe, full of a jelly-like substance called the vitreous. Lining the inside of this eyeball is a tissue called the retina. It is thin and delicate like plastic wrap, Kellaway observes. “It is like the film in the camera. The retina actually does the seeing and has millions and millions of nerve connections that group together and form the optic nerve, which then goes to the brain.”
The eye’s clear outer covering is the cornea. The blue-, green- or brown-pigmented part of the eye is called the iris — an opening that regulates the light entering the eye.
“The eye works like a camera,” explains Kellaway. “Light bounced off of objects in our environment enters the opening of the iris and is focused by the cornea and the lens. The image falls upside down and backwards at the back of the eye.
“The most powerful bending of light occurs at the cornea and lens, focusing sharply on the retina,” she says. Interrupting this pathway creates blurry vision.
“A mature cataract is like a peanut M&M. The human lens gets very hard in the middle like the peanut in the M&M, surrounded by the easier-to-remove cortex, all wrapped up by the tough membrane,” explains Kellaway.
In the past, no technology was available to break up the “peanut” at the center and pull it out, so to remove the cataract was a major operation. After the procedure, the patient had to stay immobilized for weeks.
Luckily, technology has progressed. “Today, we do an incision (about 2 1/2-3 mm) and use ultrasound waves to break up the nucleus and remove parts of it. Then we aspirate the softer cortex material. We can clean out all the discoloration. In that 3mm incision we insert the folded lens and unfold it. Leaving the ‘candy shell’ intact really helps a person avoid further cataract surgery.”
Cataracts are the most prevalent age-related eye disease in the world and, according to the World Health Organization, the leading cause of blindness. Cataracts affect more than half of all Americans by the age of 80.
Floaters, bits of protein and other debris that move in front of the retina are perfectly normal, she says, but if you notice a sudden change in your floaters or there are flashes of light — like lightning — it can be a warning of retinal problems.
“The jelly inside the eye contains collagen and cells. The jelly is lightly attached to the retina in certain places. With time, nearsightedness, trauma or [anything that creates] traction on these attachments may tear a hole through which blood or pigment leaks. Then if the retina is lifted off the back wall, that’s a retinal detachment.”
If treated early enough, some retinal tears can be repaired with new laser surgery techniques, which can prevent the more serious retinal detachment problem. So it’s important to alert your eye doctor quickly if you think you have a problem.
High pressure in the eye presses on the nerve and gradually, over time, kills off the nerve and vision. Millions of us walk around not knowing we have glaucoma, a significant cause of blindness. It can be treated, but the earlier it is found, the better. Risk factors are time, a close relative with it, African-American heritage, and high ocular pressure. Annual eye exams should include a test for glaucoma.
Retinal Vein Occlusion
A clot causes blood flow in the retina to back up, and leads to serious loss of vision. Bleeding into the delicate retinal tissue causes damage to the retina in people with diabetes or high blood pressure. It’s often associated with glaucoma. Vision cannot be restored, but exams can watch for other things that might cause further vision loss.
Changes to small blood vessels in the retina clog up the tiny capillary vessels and cut off the blood supply. The tissue starves for nutrients. Protective cells on vessel walls fall off, leading to the formation of aneurysms, which leak blood and fluid into the retina.
In later stages, the body produces new blood vessels to try to feed the eye, but instead, leak fluid, cause hemorrhage and more problems.
Annual eye exams, from the time of diagnosis, are imperative for diabetics. Frequent checks of glucose, blood pressure and cholesterol also are important.
The macula is where the best center vision is. Waste material that cannot be eliminated normally will eventually create blockages. In about 10 percent of the cases, the central vision is severely affected by hemorrhage.
Currently, there is no cure and the exact cause is unknown, but risk factors include age, having fair skin and blue eyes, and smoking. The best ways to avoid severe problems are to watch your blood pressure, stop smoking, and eat green leafy vegetables. Antioxidant vitamin supplements may also help avoid problems. Future technology may help us.
Dry eye is a common problem affecting millions of people. With aging, there is a change in the amount of tears produced leading to burning and irritation. Sometimes dry eyes are the result of systemic diseases like thyroid dysfunction or an autoimmune disease.
Usually the treatment is simple such as replacing the moisture by using artificial tears or increasing the retention of natural tears by inserting tiny plastic plugs into the “tear duct” punctum, the place where tears drain into the nose. More severe cases may require aggressive treatment with immunological agents in order to prevent serious damage to the cornea and ocular surface.
The best way to ward off eye problems, Kellaway reiterates, is to get a complete annual eye exam. Most problems can be halted or reversed with early detection.
UPDATED: 4-28-2003
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Dr. Judianne Kellaway is associate professor of ophthalmology at the UT Medical School.
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