June 2017

 

COVER FEATURE

 

Rebirth of laser vision correction
Looking at LASIK’s advances


by Vanessa Caceres EyeWorld Contributing Writer

   

The higher order aberration ablation treatment pattern, which was added to the standard myopic and astigmatism profile. Best corrected vision with glasses was 20/15 preop and 20/12 postop.
Source: Francis Price Jr., MD


Summit OmniMed laser (1990s)
Source: Daniel Durrie, MD


Surgeons and industry continue to improve outcomes and boost patient satisfaction

Since its 1999 approval by the U.S. Food and Drug Administration (FDA), LASIK has been an effective vision correcting procedure, and its potential to improve vision has continued to evolve.
When LASIK was first approved, 90% of patients achieved 20/40 uncorrected visual acuity (UCVA); 50% to 60% of patients achieved 20/20, said Daniel Durrie, MD, clinical professor of ophthalmology, University of Kansas Medical Center, and founder, Durrie Vision, Overland Park, Kansas. “At that point, we could say there was a high likelihood that patients would pass their driving test without glasses, but we couldn’t say they would see better than with their glasses,” he said.
As technology has improved and as refractive surgeons have focused on better patient screening, the percentage of patients achieving 20/20 is more than 90%, according to a report from Sandoval et al. last year.1 The Sandoval report was a review of articles about LASIK and encompassed nearly 68,000 patients.
A 2013 study of U.S. Navy aviators found that 98.3% of patients with myopia or mixed astigmatism had a UCVA of 20/20 or better.2
The Patient-Reported Outcomes With LASIK (PROWL) studies from the FDA found that 95% of patients had 20/20 or better binocular UCVA at 3 months postoperatively.3
There’s a greater number of patients achieving 20/15 or even 20/12 UCVA now, thanks to recent advances like topography-guided LASIK, said Francis Price Jr., MD, founder, Price Vision Group, Indianapolis, and president of the board, Cornea Research Foundation of America.
“The discussion over the last 15 years has been whether we could make people see better than with glasses. It’s taken some work, but I think that’s where we’ve arrived today,” Dr. Durrie said.

LASIK technology

One impetus behind LASIK advances has been the evolution of technology. “It’s fun to look back. I was in the first clinical trials [for LASIK], and we had this argon fluoride laser and were trying to figure out how to use it. We were discussing if we should be opening or closing the diaphragm and where to center the procedure,” Dr. Durrie said.
Tracking systems were developed through time so surgeons didn’t have to worry about patients moving. Iris registration was developed to handle an eye that torqued or turned.
Flying and variable spot lasers were a major technological breakthrough because they made the procedure more flexible and helped surgeons correct more errors, Dr. Durrie said.
The development of larger optical zones helped cut down on the amount of glare and halos that early treated patients experienced, Dr. Price said. “When we started transition zones, we virtually eliminated glare and halos and problems with pupil size,” he said.
Wavefront-guided and wavefront-optimized technology also helped to advance LASIK accuracy.
The use of the femtosecond laser for flap creation instead of the mechanical microkeratome helped make LASIK safer, said Elizabeth Hofmeister, MD, refractive surgery advisor for Navy Ophthalmology, San Diego. “This allows us to create flaps with much greater precision and safety than a bladed microkeratome. We can also create a ‘reverse bevel’ to create a dovetailed fit of the flap back into its bed, reducing the chance of late flap dislocations,” she said. Studies in the U.S. Navy have shown that LASIK flaps are stable to blast injuries and G-forces, Dr. Hofmeister added.

LASIK complications, side effects

Glare, halos, and dry eye are all complications or side effects associated with LASIK through time. Yet recent research shows these side effects, if they occur at all, are transient.
“Patients can be symptomatic early on but at 3 to 6 months, the incidence of dry eye postoperatively is still fairly small,” said Kerry Solomon, MD, Carolina Eyecare, Charleston, South Carolina. “Most recent studies indicate that LASIK tends to make dry eye better.”
Similarly, night vision and glare tend to get better for patients, although there is a small subset of patients who continue to experience problems with these, Dr. Solomon said. This is something that the PROWL investigators reported3—still, even in these patients, satisfaction with the procedure was higher than 95%, Dr. Solomon added.
Even with the low risk for complications, Dr. Durrie thinks it is
crucial to discuss the possibility of them with patients. However, he emphasizes that major complications like vision loss, infection, or retinal issues are rare. “The incidence is 1 in 10,000 in the U.S. We’ve done more than 55,000 procedures [at our practice] and never had a patient with major, long-term vision loss. That’s not to say everyone is perfect, but I always say if you use modern equipment, keep a sterile OR, and choose patients properly, you’ll keep your risks low,” Dr. Durrie said.
Although the need for a LASIK enhancement is not a safety issue, patients may perceive it as such, Dr. Durrie said. “The incidence of needing an enhancement is about 3%. Patients are reassured to know that 97% of the time, they’re done [in one procedure],” he said.

Safety and contact lenses

Many patients who have LASIK have used contact lenses in the past and had trouble with them or simply got tired of the daily routine. One area of interest to surgeons—and patients—is how modern LASIK fares against contact lenses in terms of safety and patient satisfaction. A study published last year and led by Marianne Price, PhD, Indianapolis, found that compared with contact lens use, LASIK improved night driving and had higher patient satisfaction levels at 1, 2, and 3 years of follow up.4 LASIK also significantly decreased self-reported rates of eye infections, ulcers, and abrasions and did not significantly raise the incidence of dry eye symptoms. Dry eye symptoms were increased, however, compared with baseline of glasses.
The study included 1,800 subjects who had LASIK or continued using contact lenses at 20 sites around the U.S. LASIK patients had higher levels of patient satisfaction compared with those continuing to use contact lenses and glasses.
There’s an underappreciated safety aspect when you compare LASIK and contact lens use, Dr. Price thinks. “With LASIK, you have doctors paying attention to screening and treatment protocols. For contact lenses, [safety] comes down to each user,” he said. Dr. Price was a co-investigator of the recently published study comparing LASIK and contact lenses with Dr. Marianne Price.
“I have taken care of many patients who have required corneal transplants after visually devastating central corneal ulcers associated with contact lenses,” Dr. Hofmeister said. “They carry greater dangers than many people realize,” especially in a military environment, she added.

Patient satisfaction

One factor not tracked with LASIK early on was patient satisfaction. This led to some concern from the FDA, Dr. Price said. Since then, studies have found consistent reports of high patient satisfaction; the study from Sandoval et al. reported an overall 98.7% satisfaction rate with LASIK, and the PROWL research found more than a 95% satisfaction rate.1,3 The high level of satisfaction is for several reasons, said Dr. Solomon, who was a co-investigator in the Sandoval study. “We’re doing a better job at patient selection, we have better technology to assist with the screening process, and we have better technology to create flaps and better lasers to perform ablations,” he said. “There’s been a lot of research and development devoted to LASIK.”
The use of validated questionnaires like the one developed through PROWL can help refractive surgeons continue to monitor for outcomes and visual quality, surgeons said.

Future of LASIK

Just as a great deal of research has led to LASIK advances in the first decades of the procedure, more advances will continue. More sophisticated diagnostic technology that spurs continuous quality improvement will likely refine the procedure, as will the addition of topography, Dr. Durrie thinks.
Even though LASIK fell on hard times during the recession, Dr. Durrie regularly has parents—many of whom had LASIK—now bringing their older children to his practice and asking when they can have LASIK. This and the large number of people who can’t seem to stick to contact lenses point toward an untapped market, he said.
The addition of new refractive procedures like small incision lenticule extraction (SMILE, Carl Zeiss Meditec, Jena, Germany) shows a renewed interest in LASIK procedures, Dr. Durrie said.
“SMILE may be comparable someday but not now. For now, we can get out the story about how safe LASIK is,” Dr. Price said. “I think we’ll see more and more people have LASIK. If LASIK is done correctly, it’s extremely safe and predictable.”

References

1. Sandoval HP, et al. Modern laser in situ keratomileusis outcomes. J Cataract Refract Surg. 2016;42:1224–1234.
2. Tanzer DJ, et al. Laser in situ keratomileusis in United States Naval Aviators. J Cataract Refract Surg. 2013;39:1047–1058.
3. Eydelman M, et al. Symptoms and satisfaction of patients in the Patient-Reported Outcomes With Laser In Situ Keratomileusis studies. JAMA Ophthalmol. 2017;135:13–22.
4. Price MO, et al. Three-year longitudinal survey comparing visual satisfaction with LASIK and contact lenses. Ophthalmology. 2016;123:1659–1666.

Editors’ note: Dr. Durrie has financial interests with Johnson & Johnson Vision (Santa Ana, California) and Alcon (Fort Worth, Texas). Dr. Solomon has financial interests with Alcon. Drs. Hofmeister and Price have no financial interests related to their comments. The views and opinions expressed by Dr. Hofmeister are her own and do not necessarily reflect the official position of the U.S. Navy, Department of Defense or Federal Government.

Contact information

Durrie: ddurrie@durrievision.com
Hofmeister: elizabeth.m.hofmeister.mil@mail.mil
Price: fprice@pricevisiongroup.net
Solomon: Kerry.solomon@carolinaeyecare.com