25 Years in Myopia: Surgical Advances Improve Vision

Jan. 3, 2010— -- When ophthalmologist Dr. James Salz first saw Nancy (who requested that only her first name be used), severe myopia left her completely reliant on glasses and contacts. Without them, the Los Angeles city employee and mother of two had vision so poor that she couldn't even recognize her children.

"When I woke up in the morning and they ran up to me, I couldn't tell who was who," she said. "When I was at the beach, I couldn't see where my family was. I basically was pretty paralyzed without my contacts or my glasses."

That's how things would have stayed 25 years ago.

Surgery that could eliminate the cause of nearsightedness by changing the curvature of the cornea was still a highly criticized idea in 1984, remembered Salz, who led some of the early studies and went on to be involved in every form of refractive surgery since then.

Today, refractive surgery is one of the most common of all surgical procedures, second only to cataract surgery in the United States.

This rapid revolution not only provided a cure for myopia but altered how we think about nearsightedness itself.

Seeing Deeper

In 1984, Nancy's eyes would have been considered healthy, just with refraction on the far spectrum of normal, like the range of human height from short to tall.

"At a typical exam, we'd say, 'Oh, your eyes are perfectly fine. You just need glasses," said Dr. Penny Asbell, director of the cornea service and refractive surgery at Mount Sinai School of Medicine in New York City.

Glasses and contacts remain the most common option for managing myopia. And there have been substantial improvements over the past quarter century in both, noted Salz, now of Cedars-Sinai Medical Center and the University of Southern California, both in Los Angeles.

Thinner, more attractive progressive bifocals and disposable, gas-permeable contact lenses have made visual correction easier on patients than ever, he said.

But it was only after refractive surgery offered a treatment that could actually get to the cause of the problem that "we started to realize that for many people myopia is, in fact, a disability and one they would rather not have if they had a choice," Asbell told MedPage Today.

Crude Measures

It's little surprise that operating on what was considered an otherwise healthy eye was once controversial. Early attempts to cure myopia were disastrous.

During World War II, a Japanese professor pioneered a form of eye surgery called radial keratotomy in which he cut through to the inner surface of the cornea to flatten out its curvature and thus reduce nearsightedness.

The procedure produced initially good results in the many young men -- who, for all intents and purposes, were experimented upon – as a result of the tremendous pressure to increase Japan's fighting force.

But over the next four to five years, their vision dramatically deteriorated as the cornea weakened.

"It wasn't really appreciated that the endothelial surface of the cornea, the interior surface of the cornea, those cells were important to keeping the cornea clear," explained Dr. Jay Pepose, an ophthalmologist at Washington University in St. Louis.

Russian surgeons revived the procedure in the 1970s with a technique that used radial incisions into the outer surface of the cornea, avoiding the problem of damage to the endothelial cell surface.

But the procedure was still crude, involving a razor blade fragment held freehand with a depth gauge used to determine how far to incise.

Normal Sight Nears

A few American surgeons flew to the then-Soviet Union to observe, and the techniques they brought back were altered to improve safety. Standardized diamond-tipped tools they developed helped as well.

By 1984, radial keratotomy was still considered controversial.

But the promise was there, recalled Dr. Robert Maloney of the Jules Stein Eye Institute at the University of California Los Angeles.

His typical conversation with a patient considering the procedure in 1984 would go something like this:

"The operation usually doesn't lead to 20/20 vision, but we can usually reduce your nearsightedness enough that you can drive a car without glasses during the day.

"However, night driving can be hindered by severe glare from the incisions. Risks of the operation include perforation of the eye if the incisions are made too deep, and farsightedness if we overshoot.

"You will have a lot of pain for a week, and your vision will be blurry for several weeks."

The first real clinical trial -- PERK (Prospective Evaluation of Radial Keratotomy) -- published positive results in 1985, but Salz, one of only 10 U.S. surgeons who participated in that trial, remembered taking a lot of criticism for it.

Then word came of an investigational method using lasers to make the cuts, he recalled.

"We went to see the first laser patients in New Orleans in about 1988/1989," Salz told MedPage Today. "It was exciting to see eyes that looked normal."

Whereas radial keratotomy left scars in the cornea that created glare and halos, laser procedures left virtually no mark.

Focus on Innovation

Outside the U.S., a parallel line of research had been underway that would make refractive surgery possible for patients like Nancy with high-order refractive errors.

One research group would remove a small part of a myopic cornea, freeze it, and essentially lathe it into a shape that would resolve the refractive error before reattaching it, Pepose said.

Although this approach never gained popularity, it did lead to development of precision instruments called keratomes or microkeratomes to remove thin slices of cornea, he noted.

Then researchers realized that lasers could do the same thing more accurately, leading to the birth of photorefractive keratoplasty (PRK) and then LASIK, as laser-assisted in situ keratomileusis is more popularly known.

By 1995, the excimer laser gained FDA approval for surface treatments, setting off an explosion in the number of refractive procedures done.

"The procedure has just gotten better and better and better," Salz said in an interview.

One major step forward was computer mapping of the exact topography of the cornea, Pepose explained. Wavefront-guided procedures now allow treatment of astigmatism and higher-order aberrations, he said.

Nancy's high diopter myopia almost made her a candidate for the newest treatment for myopia, artificial implants placed on top of the natural lens, which Pepose described as "almost like implantable contact lenses."

These intraocular lenses haven't caught on much yet in the U.S. because of concern about long-term outcomes but may be the future of myopia treatment with further advances, Asbell said.

However, Nancy's cornea was thick enough to allow LASIK using a technique that removes less tissue, which Dr. Salz performed late last year.

A Kinder Cut

The quality of vision offered by modern refractive surgery is actually better than glasses or contacts could offer 25 years ago, Pepose noted.

"Glasses make the world smaller when you're myopic" – 2 percent per diopter, he said in an interview. "A -10 myope in glasses sees the world 20 percent smaller."

Like any surgery, refractive correction involves some risk, ranging from dry eyes and halos to the rarer complications of infection and even blindness.

LASIK substantially cut down on healing time and risk by using a "flap," with the surface peeled back as if on a hinge and then reattached after removing just a sliver of cornea underneath.

This relatively simple change represented a tremendous advance in patient acceptance, Pepose said.

"It took a procedure, which wasn't technically difficult to perform, but had a longer recovery for the patient -- four or five days during which they were light sensitive, they weren't seeing well, they were uncomfortable," he told MedPage Today, "and it converted it to a surgery where literally patients would have the procedure, go home, take a two-hour nap, and wake up and see with no discomfort."

The outcomes have improved over time as well.

With radial keratotomy, fewer than 50 percent of patients, typically mild to moderate myopes, reached 20/20 vision. Today, almost all patients get 20/20 vision with a single LASIK procedure, Salz said. "It's accurate almost beyond belief."

Nancy was ecstatic about her results.

"I wake up every day amazed that these are my eyes," she said. "Now I'm almost seeing 20/20. It's great. It's actually unbelievable."

And she isn't alone, Salz said.

"For some patients this is a life-changing experience," he said. "These people sometimes will just cry when they see how well they can see."