Tuesday, Nov. 29, 2005
If you have always wanted a permanent solution to wearing glasses, then spend just 15 minutes under the laser and you can say adios to those ugly frames. Laser surgery is popular, largely painless and every effective.
LASIK is a 15-minute operation that uses a laser to reshape the cornea. It can correct nearsightedness, farsightedness and astigmatism. For most people, the recovery period is at most a few days. [How to See Like a Hawk When You’re Blind as a Bat : A Patient’s Guide to LASIK Laser Vision Correction]
But LASIK, which stands for laser in situ keratomileusis, is not without its share of problems. A study published in the January 1999 Ophthalmology documented complications in 5 per cent of cases. A very small number of people do end up with worse eyesight.
Here are a few things you have to keep in mind before opting for the surgery.
• If you are over 40, LASIK probably does not mean goodbye to glasses. You’ll still need them for reading or doing close work. Some people avoid reading glasses by getting just one eye treated, which balances out their vision: one eye for seeing things up close.
• Don’t expect 20/20 vision. The vast majority of people who undergo LASIK do so to correct nearsightedness. Most of them end up with vision somewhere between 20/20 and 20/40 (a person with 20/40 vision needs to stand 20 feet away from something that a person with 20/20 vision can see fine from 40 feet away).
• Considering that people with even a mild correction tend to have 20/100 vision or worse, that is a huge gain. But if you are used to glasses or contact lenses, which correct your vision to 20/20, uncorrected vision of 20/40 after LASIK may seem like a setback.
There could be other problems after surgery, too. Some people see halos around streetlights, others suffer from contrast sensitivity. Moreover, if you are a diabetic, it is better to avoid LASIK surgery. Get your doctor to enlighten you about both the advantages and the disadvantages.
• Reshaping the eye with a laser can cause some distortion in the eye’s optics that decreases what ophthalmologists call ‘contrast sensitivity’—the narrowing of difference between dark and light.
It is roughly analogous to a photograph that is in focus but too grey. Sometimes the loss of contrast sensitivity is described as adding a ghostliness or fuzziness to vision. The reason for this optical distortion following a LASIK and other laser operations is not yet known.
• While the recovery period from LASIK is remarkably short, 30 per cent to 40 per cent of people see halos or ‘starbursts’ around bright lights for several months. This effect seems to be caused by the edge between the treated and the untreated part of the cornea bending and distorting the way light hits the eye.
People with exceptionally large pupils should not opt for LASIK surgery because the starburst effect could remain a permanent problem for them.
• People with extra-thin corneas are not good candidates because the surgeon needs enough tissue to work with. The thickness of the cornea is not necessarily related to vision. So the only way of knowing if your corneas are thick enough is to have them measured by an ophthalmologist.
Some ophthalmologists also turn away people with rheumatoid arthritis and lupus because they can have problems with dry eyes and recovery from LASIK involves some drying out of the eyes. People with diabetes also may not be ideal LASIK candidates because the outermost layer of their cornea, the epithelium, is thin and they have decreased corneal sensation.
• Finally, people who are candidates for a cataract surgery shouldn’t choose LASIK. A cataract is a cloudy lens; operating on cataracts involves taking out the clouded lens and replacing it with a new plastic or silicon version. Artificial lens implants can correct nearsightedness or farsightedness just as well as LASIK. So, there is no point in having both the procedures.
Wednesday, Nov. 2, 2005
Barb Merriman was tethered to her first pair of eyeglasses at age 7. Without them, she was lost – literally.
“To go swimming with my friends, I couldn’t tell who my friends were,” she said. “I would have to tell them to come find me.”
As an adult, Merriman’s sight deteriorated so much that she couldn’t read the alarm clock on her bedside table without her glasses on. To read printed material, she had to hold it so close to her face that her eyes crossed.
Her glasses were a quarter-inch thick despite being outfitted with high index, or extra-thin, lenses. At work, she wore prescription safety glasses.
“It was like you were looking through a diving bell,” she said. “I hated wearing them.”
She felt disabled.
Sight “is our most precious sense,” Merriman said. “We take in so much through our eyes.”
The Billings woman waited 20 years for a corrective procedure that could help her – she was too near-sighted for Lasik surgery – and, last summer, it finally arrived.
Merriman underwent intraocular surgery, in which hard plastic lenses were implanted inside her eyes.
“Compared to glasses and contacts, I’d take this any day,” she said. “It is just like having no vision correction at all.”
Intraocular surgery was approved by the Food and Drug Administration about a year ago and is the only FDA approved surgery of its kind, said Dr. Mohammad Karbassi, an ophthalmologist at Billings Clinic who performed Merriman’s surgery.
Karbassi said intraocular technology first emerged in the 1950s but only recently was refined enough for public consumption. It is similar to the technology used for cataract surgery.
In separate procedures, Karbassi slipped a tiny plastic lens into each of Merriman’s eyes through a 6 mm incision and clipped it to her iris.
“The beauty of this is it’s reversible,” Karbassi said. “It also doesn’t alter the shape of the cornea.”
In Lasik surgery, which Karbassi also performs, layers of the cornea are shaved off to correct a patient’s vision.
“The more near-sightedness you are correcting, the more you are shaving off,” Karbassi said. “There has to be a limit.”
No Lasik surgery
Merriman’s eyes were beyond the limit, and she did not qualify for Lasik surgery.
She read about intraocular surgery in the newspaper shortly after it was FDA-approved last year.
“I said, ‘OK, this is what I’ve been saving my money for,'” she said. “I figured I’d have to go to a big city to have it done. We had it right here in Montana.”
Merriman said her eyes felt uncomfortable for about a day after each surgery, but she could immediately see clearly.
“The worst of the whole thing was getting the IV needle,” she said.
She cannot feel the lenses in her eyes, but she can see them in the mirror if she shines a bright light on herself.
There are risks associated with the surgery, including infections and long-term damage to the cornea. But to Merriman, the risks were minor.
“It’s the best money I ever spent,” she said. “I would have paid more.”
Thursday, Aug. 18, 2005
In an effort to combine sophisticated laser and Internet technologies, scientists in Australia have successfully performed laser surgery and “optical trapping” in a Southern California laboratory via the Internet.
The scientists used a new Internet-based laser scissor-and-tweezers technology called RoboLase, demonstrating the potential of using the technology for real-time research activities between laboratories and for physicians to perform medical procedures from distant locations.
In a proof-of-principle series of experiments, the scientists from UC Irvine, UC San Diego and the University of Queensland employed RoboLase to produce surgical holes in a distinct pattern of less than one micron in diameter (1/1000th of a millimeter) in single cells. Utilizing a control panel projected onto a computer screen, Queensland researchers were able to remotely perform the cell surgery on a laser microscope system in the Southern California laboratory.
“The speed and precision of the sub-cellular surgery was equal to what it would be like if we were doing the same surgery in our labs here in California,” said Michael Berns, professor of biomedical engineering at UCI and adjunct professor of bioengineering at UCSD, who led the development of the RoboLase technology.
In addition, the scientists were able to grab onto – or “optically trap” – swimming sperm in the California lab by operating optical-laser tweezers remotely from Australia. This was a particularly noteworthy accomplishment, because it demonstrated the amount of computer bandwidth (1 gigabyte/second) needed by the Australia and California research groups to observe and grab a fast-moving sperm with virtually no detectible delay in image transmission between the two laboratories.
“If there was a detectible delay in either the transmission or reception of the video images, our colleagues in Australia would not have been able to identify and trap a targeted sperm under the laser microscope in the California laboratory,” added Linda Shi of UCSD, one of the key developers of the unique computer software that was used in the sperm-trapping experiments.
According to Berns, who is the founding director of the Beckman Laser Institute at UCI, the general significance of this work is that researchers can now collaborate on experiments with scientists around the world using this expensive and sophisticated instrumentation without having to travel to a single laboratory site. It also serves to demonstrate that the Internet will become increasingly more useful and important for the actual conduct of scientific research and possibly for the delivery of selective medical procedures.
“This technology is now accessible to other scientists who may not have easy access to it,” added Elliot Botvinick, a Beckman Fellow at UCI and co-developer of the RoboLase technology. “And the instrumentation can be used over the Internet as a learning tool by students just about anywhere in the world.”
The research is being presented today at the International Society for Optical Engineering meeting in San Diego and will be published in the September issue of the journal Microscopy Research and Technique.
Halina Rubensztein-Dunlop, professor of physics and head of the team at the University of Queensland, participated in study, which received funding support from the United States Air Force, the National Institutes of Health and the Arnold and Mabel Beckman Foundation.
Saturday, Aug. 13, 2005
Dave Wallace found himself in quite a quandary. The 76-year-old River Bend resident suffered from cataracts and disliked wearing glasses. Yet as an avid cyclist, he needed to see the road.
“My vision was going down and I was concerned about keeping my driver’s license,” he said. “But I hate glasses. I’ve hated them all my life.”
Thanks to a new procedure, Wallace didn’t have to choose between restoring his vision and keeping glasses away from his face.
The procedure entails the insertion of a presbyopia-correcting intra-ocular lens. The multifocal lens, sold by Alcon as Acrysof ResTOR IOL, corrects vision both up close and at a distance. About 80 percent of patients who undergo the procedure no longer require glasses.
“The demand (for the procedure) has increased since Medicare recognized it in May,” said Rozanne McCotter of Coastal Eye Clinic in New Bern. “Now, it’s very widely performed.”
The lens was first introduced in Europe in 2003. Clinical trials in the United States led the Food and Drug Administration to approve the lens in March. According to McCotter, two years of testing has rendered the procedure relatively free of drawbacks.
In addition to its use in cataract surgery, the lens presents an alternative to other vision correctives.
“It’s very comparable in cost to LASIK surgery,” McCotter said of the laser-eye surgery to correct poor vision. “LASIK patients are also still reliant on reading glasses.”
Like LASIK surgery, the IOL insertion costs several thousand dollars. For cataract patients, part of that cost is covered by Medicare.
Dr. Kenneth Chance of Coastal Eye Clinic said the procedure is likely to grow in popularity for people age 50 and older. He has performed the procedure on three different patients.
“When I first heard about it, it seemed almost too good to be true,” he said.
Wallace, who was the first of his patients to receive the lens, shared his enthusiasm.
“I found out about it on the Web and was very eager to try it,” he said
The results so far have been positive – Wallace described life after the procedure as “a bright new world.”
The lens, however, did not correct Wallace’s occasional double vision, a pre-existing condition that might lead him toward prism-correcting glasses after all.
The cost of the procedure varies according to the type of lens, but it is covered partially under Medicare for cataract patients.