Technology leads to advances in vision correction

Unlike many medical advancements which are the result of years of laboratory research by physicians and scientists, advances in corrective eye surgery are frequently developed by technology gurus.

Radial keratotomy (RK), one of the first corrective procedures used in the 1970s, changed the shape of the cornea by making incisions with a surgical knife. As equipment became computerized and lasers came into use, results improved dramatically.

“When the laser came in, it was so much better than RK and produced much more stable results,” said Dr. Mitchell Friedlaender, head of Scripps Ophthalmology and director of the Laser Vision Center in La Jolla.

Photorefractive keratectomy (PRK) was one of the first procedures to use a laser beam to treat the surface of the cornea. Still, there were drawbacks: This procedure was effective with only a few conditions, was uncomfortable for some patients and healing was slow.

By the 1990s, laser-assisted in situ keratomileusis (LASIK) had overcome these problems by creating a flap in the delicate surface of the cornea so the laser passed through to the layers beneath.

Still, because the flap was created with a hand-held device called a microkeratome, there was potential for flaps to be too thick, too thin or irregular.

Development of bladeless LASIK, also known as IntraLase for the first FDA-approved manufacturer of femtosecond technology, uses a laser to create the flap instead of a microkeratome, improving accuracy.

Wavefront technology, a process that measures vision errors by identifying the way light waves travel through the eye, allows physicians to perform “custom corneal ablation,” or, in other words, correct higher order optical imperfections such as glare, distortions or halos.

Another software advancement that has contributed to the efficacy of corrective eye surgery is iris registration, software that enables the laser to compensate for rotary movement of the eye.

Conditions such as nearsightedness (myopia), farsightedness (hyperopia) and astigmatism can usually be corrected by surgery, but other problems aren’t as easily fixed Friedlaender calls presbyopia, the need for reading glasses after age 42, the “holy grail” of laser vision.

Monovision is one technique used to compensate for presbyopia. In this procedure, one eye is corrected for distance and the other for near-range sight. Eye glasses simulating this effect can help patients decide if they are comfortable with this dual perception.

Research is being conducted on creating a “bifocal” laser pattern on the cornea, but Friedlaender said the procedure still needs refinement.

“If someone figured out how to correct presbyopia, that would be a tremendous boon to society,” he said.

Improvements in existing technology and new techniques have made is possible to treat conditions once excluded from corrective surgery. Yet, as with all medical treatments, patients should carefully evaluate the limitations and possible side effects before committing to the procedure.

“It’s no panacea,” Friedlaender said. “It’s not for everybody.”

While considered an elective procedure, the potential for improved quality of life makes corrective eye surgery worth the expense for many individuals. Not only does it reduce dependence on glasses or contact lenses, it enables many to pursue hobbies, sports and careers previously unavailable to them.

“This is a lifestyle change,” said Dr. David Schanzlin, director of Refractive Surgery at Shiley Eye Center. “This really affects peoples’ lives.”

LASIK procedures cost an average of $4,500 to $5,000 at facilities such as Scripps Laser Vision Center and Shiley Eye Center.

Both Friedlaender and Schanzlin stressed the importance of having a corrective procedure performed by an experienced practitioner. Working with a qualified physician can alleviate much of the worry and concern about undergoing such a delicate operation.

“Who can blame them?” Schanzlin said. “But once they get educated and understand how safe it is, the fear goes down.”

For additional information about corrective eye surgery, visit and Additional information can be obtained by calling Shiley Eye Center at (858) 822-2566 or Scripps Laser Vision Center at (858) 554-8143.