| Back in the 1950s and 1960s, when scientists were making the discoveries that would lead to LASIK surgery, the idea of improving vision with a laser in the eye might have seemed like science fiction.But today, a decade after being introduced to the masses in the U.S., LASIK — which stands for laser-assisted in situ keratomileusis — has used precisely such a technique to bring clear vision back to millions of Americans, without pain or stitches.
“LASIK is a procedure that reshapes the cornea to allow a person to see without glasses,” said Dr. Nancy Balin, owner of the Balin Eye & Laser Center in Northampton.
“A flap is made in the cornea where a very small piece of the cornea is actually cut or lasered and laid back, and then a laser ablates, or removes, tissue in the proper pattern to reshape the cornea,” she explained. The flap then re-adheres naturally, she explained, eliminating the need for stitches.
The groundwork for LASIK was laid as early as 1950, when Jose Barraquer, a Colombian ophthalmologist, developed the first microkeratome, a device used to cut thin flaps in the cornea and alter its shape.
The other key development was the 1968 creation of the Excimer laser, by which molecules that do not normally exist come into being when xenon, argon, or krypton gases are excited. This would form the cornerstone for today’s LASIK eye surgery.
The precursor to LASIK, radial keratotomy, uses a very sharp knife to cut slits in the cornea, changing its shape. Following that development in the 1970s was the introduction in the 1980s of photorefractive keratectomy (PRK), the first surgical procedure to use a laser to resculpt the cornea.
LASIK uses the same type of laser as in PRK. The difference lies in how the middle layer of the cornea, the stroma, is exposed before being vaporized with the laser. In PRK, the top layer of the cornea, called the epithelium, is scraped away to expose the stromal layer underneath. In LASIK, a flap is cut in the stromal layer and the flap is folded back.
Compared to LASIK, “it takes longer to set,” Balin said of the recovery time from PRK. “The recovery of vision occurs slowly over the first week, then refines itself over weeks or months. LASIK, on the other hand, gives rapid recovery — to the point where many people come in the next day with 20/20 vision.”
“The flap adheres through a negative-pressure phenomenon which is intrinsic to the cornea,” said Dr. John Frangie, owner of NorthEast Laser Center in West Springfield. “If you replace the flap in good position, the cornea has cells that create a low-level vacuum, and over the course of days the healing process begins. The flap also has proteins and cells that proliferate to give it long-term stability.”
All of this, he added, is accomplished with minimal discomfort to the patient, who is given a low-level sedative but is completely cognizant throughout the LASIK procedure.
Risks and Rewards
According to the U.S. Food and Drug Administration, most patients are pleased with the results of their LASIK surgery, and studies consistently suggest a satisfaction rate well above 90{06cf2b9696b159f874511d23dbc893eb1ac83014175ed30550cfff22781411e5}. However, the FDA does note that, because it’s a relatively new technology, long-term data from LASIK is unavailable. For now, the agency cautions about several possible risks:
- Some patients lose vision. Some have lost lines of vision on the vision chart that cannot be corrected with glasses, contact lenses, or surgery as a result of treatment.
- Some patients develop debilitating visual symptoms, such as glare, halos, and/or double vision that can seriously affect nighttime vision. Even with good vision on the vision chart, some patients do not see as well in situations of low contrast, such as at night or in fog, after treatment.
- Patients may be undertreated or overtreated. Only a certain percent of patients achieve 20/20 vision without glasses or contacts. Some may require additional treatment, or may still need glasses or contact lenses — for reading, for instance — after surgery.
- Some patients may develop severe dry-eye syndrome. As a result of surgery, the eye may not be able to produce enough tears to stay moist and comfortable. Dry eye, a sometimes-permanent condition, not only causes discomfort, but can reduce visual quality due to intermittent blurring and other visual symptoms. Intensive drop therapy and use of plugs or other procedures may be required.
- Results are generally not as good in patients with very large refractive errors of any type. And for some farsighted patients, results may diminish with age.
To minimize potential complications, said Frangie, patients who have certain pre-existing conditions, such as severe dry eye, glaucoma, and cataracts, are counseled against LASIK.
“The patients best-suited for this procedure are those who don’t have any coincidental ocular pathology,” he said. Part of the reason is liability — or at least the practice’s reputation — if something goes wrong in the future. Because many such pre-existing conditions are progressive, he explained, it’s possible for patients to complain about their vision getting worse after LASIK, when the surgery had nothing to do with it.
“I don’t like to confuse the issue,” said Frangie. “I like to make sure that anyone we operate on enjoys the benefits of committing the time, money, and spirit to LASIK.”
Still, Frangie said, “there are really very few limitations in patients who don’t have that active pathology. And it’s improving; today, we use a different procedure than the one we delivered six years ago when we started.”
Specifically, he explained, a computer readout of the cornea today allows doctors to deliver a more precise laser than in the past, when it was merely programmed to the eyeglass prescription. LASIK may also be delivered without any cutting today, thanks to a breakthrough called IntraLase, which has expanded the range of patients who can undergo the procedure. “It really has unsurpassed safety,” he said.
Into the Future
Through developments like ‘wavefront’ LASIK that allows for custom corneal scans, Balin said laser eye surgery can improve the vision of patients with a wide range of refractive errors, including nearsightedness, farsightedness, and astigmatism.
“As with any surgical procedure, there are risks involved, but they are quite low,” said Balin. “There might be some glare, but the risk is less than 1{06cf2b9696b159f874511d23dbc893eb1ac83014175ed30550cfff22781411e5}.”
And LASIK is becoming ever safer as new technologies emerge, she said, including iLASIK, which combines elements of IntraLase and wavefront technology and is the only LASIK technology that has been approved for Navy fighter pilots and NASA astronauts, due to its almost instantaneous recovery time.
Insurance companies typically don’t cover LASIK, which they consider cosmetic. According to national surveys conducted by www.allaboutvision.com, conventional LASIK cost an average of $1,700 per eye in 2007, while custom-cornea and IntraLase procedures typically topped $2,300 per eye.
But for those who have successfully gone under the laser, it’s simply the cost of a higher quality of life. |
