STORY BYTo those of us finally wise enough to view life clearly, it is a cruel evolutionary joke that we can no longer see life clearly. At the bare minimum, should not the length of our arms grow in direct proportion to our new short-sightedness?
Presbyopia is the formal term for imploring anyone under 30 to recite to us the total on our receipts, our prescription labels, our menus… It is the aging eyes’ diminished ability to focus on close-up tasks, which, in this era, involve everything except sleeping.
“This condition is the natural aging process of the eyes and usually begins about the age of 40,” says Richard W. Yee, M.D., professor of ophthalmology at The University of Texas Medical School at Houston and medical director of the Refractive and Cornea Unit at the Hermann Eye Center at Memorial Hermann Hospital.
So, as our generation loves to mutter: if they can put a man on the moon, can’t they restore our vision?
Yee is investigating a new surgical option to correct age-related near-vision loss as part of a Phase III Federal Drug Administration (FDA) clinical research study. If you are tired of fishing for your reading glasses, you may be interested.
“This trial is based on the theory of accommodation, which is the eye’s ability to naturally adjust its focus from distance to near objects,” explains Yee, who also holds the Joe M. Green, Jr., Endowed Chair in Ophthalmology at the medical school.
“As you age, presbyopia occurs as the crystalline lens grows larger, creating slack in the fibers of the eye that control its movement,” Yee explains. One of a variety of explanations offers that when the muscles try to contract to focus in, the fibers may be too loose to force the lens to change shape, he says.
The objective of the vision study is to evaluate the safety and effectiveness of the new surgical treatment. The devices are the scleral implants, and the scleral belt-loop creator.
The surgeon makes incisions at four points in the sclera or white of the eye around the lens. Then, scleral “belt loops” are fashioned at each point. Next, four plastic implants, each the size of a grain of rice, are inserted into the loops. The implants pull the ciliary muscles farther away from each other, decreasing the slack in the fibers. When the eyes move from a distant object to a close one, the fibers, once again, have the tension and strength to change the shape of the lens.
Patients can expect to have red eye for two to six weeks following the procedure. Short-term side effects may include pain, sensitivity to light, a feeling of "something in the eye," eyelid swelling, blurred vision, tearing, and pain around the eye when focusing on close objects.
As part of the Phase III trial, Yee has done a total of seven eyes to date, and over 50 are waiting to be screened. He will have done 120 surgeries by the time the trial ends next spring, Yee says.
In Phase II of the trial, in which Yee was not involved, 80 percent gained “three to six lines of near vision” which translates to being able to read the newspaper again with no other visual aid.
“When the findings from Phase II were submitted to the FDA in October, they were approved without revision. That was unusual and very exciting. This procedure has the possibility of being available to the public in about two years,” Yee says.
Working with presbyopia patients is not new to Yee, who did the first scleral expansion, its original name, at the Hermann Eye Center in the late 1990s. Representing the Center, he collaborated with Ronald A. Schachar, M.D., Ph.D., a Dallas eye surgeon, who developed the theory on which the clinical trial is based.
Schachar’s theorectical approach continues to be discussed. The American Academy of Ophthalmology and international vision researchers are reconsidering its understanding and definition of presbyopia.
Yee is looking for study participants who have presbyopia and are between 50 and 60 years old. If you have reading glasses, contacts or a bit of nearsightedness, farsightedness, or astigmatism, you may be eligible for the clinical trial. You are not a candidate if you wear distance glasses or have had a prior surgery on your eyes such as LASIK, RK or PRK or have a chronic eye disease.
If you are selected for surgery, you will be given a complete eye exam as well as a medical exam to determine your state of health. These preliminary activities are free. Following the procedure, you will be monitored for 24 to 30 months.
The name of the study is PresVIEWS Scleral Implant (PSI) for the Treatment of Presbyopia. Prospective participants can call 713-704-1839 or 713-704-0660. For more information, contact richard.w.yee@uth.tmc.edu.
UPDATED: 1-03-2006
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Dr. Richard Yee is a clinical professor in the Department of Ophthalmology and Visual Science at the UT Medical School.
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Tetanus booster for adults
Tetanus does not result from the rusty nail or whatever created the wound. The danger lies in the bacteria Clostridium tetani that lives in the soil or manure on that nail or gardening tool. When these spores get into a wound—deep or shallow—they can produce a potent toxin. Also called lockjaw, tetanus seriously affects the central nervous system and can be fatal.
Onset of symptoms can occur anytime from three days to three weeks. Call your health care provider if you have an open wound, particularly if:
Adults should have a tetanus booster shot every 10 years, known as the Td vaccine. It is a "2-in-1" vaccine that protects against tetanus and diphtheria. It contains a slightly different dose of diphtheria vaccine than what you received as a child. It can be given to anyone older than 7 years and is injected, usually into the arm.
Instead of the standard Td booster every 10 years, adults between the ages of 19 and 65 should receive Tdap one time in their adulthood to boost the immune system for pertussis, as well as tetanus and diphtheria.
Diphtheria, a contagious bacterial infection created that causes severe inflammation of the throat and larynx and can also affect the whole body. Pertussis or “whooping cough” is a serious bacterial infection that afflicted children and infants before vaccines were available. Adults may be infected later in life as their immunities wane. Neither of these infections are related to tetanus, but both vaccines are compatible and convenient to use with the tetanus booster.
