By Scott D. Barnes, MD, Chief Medical Officer of STAAR Surgical

When I first heard about photo refractive keratectomy (PRK), I was wearing a Green Beret and running around southeast Asia on active duty in the Army, parachuting, combat SCUBA diving, and flying helicopters.

I was eager to shed my glasses but thought the experimental vision-correcting laser eye procedure sounded risky. In fact, I was kind of terrified it would melt my eyes!

Because PRK wasn’t FDA approved, I had it done in Canada in 1991. I was so amazed at my clear vision that I vowed to become an ophthalmologist, learn to perform the procedure, and bring it back to the Army.

In the years since, I’ve studied and performed many surgeries that correct myopia, hyperopia, and astigmatism — otherwise known as nearsightedness, farsightedness, and blurriness. In addition, I’ve tried to increase awareness of these procedures by teaching colleagues and speaking at medical conferences.

Along the way, I’ve watched our toolbox of approved strategies expand to include laser surgeries that remove tissue from the cornea, procedures that add sight-enhancing technologies to the eye, and options that do both.

While some clinics specialize mainly in one surgery or another, I believe it’s essential for ophthalmologists to offer all these procedures.

It’s our responsibility to ensure that our patients not only understand their full range of surgical options but have every opportunity to meet or exceed their vision goals. After all, what investment do patients make that they rely on as much as their eyesight?

Laser Surgery Gives, and it Takes Away

The most common vision-correcting procedures involve laser surgeries that remove tissue from the cornea, flattening, steepening, or otherwise changing the curvature to correct myopia, hyperopia, and astigmatism.

These include:

• PRK, which removes part of the surface of the cornea.
• LASIK, or laser-assisted in situ keratomileuses, which creates a partial-thickness flap in the cornea, lifts it to remove tissue, and then lays the flap back down; and
• SMILE, or small incision lenticule extraction, which “cuts” a disc-shaped portion, or lenticule, to be removed through a small opening at the edge of the cornea.

Procedures that add technologies to the eye to correct the same three vision deficiencies include:

• Phakic intraocular lenses — small, flexible “contact” lenses implanted through a tiny corneal opening. These are placed behind the iris (the colored part of the eye) or clipped onto the iris while leaving the eye’s natural lens in place to allow the eye to focus at various distances; and
• Refractive lens exchange, which first removes the eye’s natural lens and then replaces it with an artificial one. This is similar to cataract surgery, except that the lens being removed is clear, rather than cloudy due to age.

Considering Eligibility

While we are still searching for the Holy Grail of total vision correction, ophthalmologists can make the most of the top-notch options we have by carefully selecting patients for procedures based on their needs.

For instance, despite its popularity, not everyone interested in laser correction is eligible for LASIK; patients with severe myopia and thin or suspicious-looking corneas may be better suited to PRK. Furthermore, historically, LASIK wasn’t the best choice for those in the military or contact sports, as a hit to the eye could damage the surgical flap; although modern, laser-created flaps have largely eliminated this occurrence, some still express concern.

LASIK also raises post-surgical considerations, as it can lead to temporary dry eye. On the other hand, it promises a quicker and more comfortable recovery than PRK, with SMILE hovering somewhere between the two regarding pros and cons.

So, where do artificial lenses fit in?

While phakic IOLs involve a different recovery than LASIK, they have been considered appropriate for patients with stronger prescriptions, maxing out at -20 D of myopia compared with -10 D for SMILE or -12 D for LASIK and PRK. However, this technology is generally restricted to younger adults whose natural lenses can still focus at close range.

Eventually, we hope that multifocal phakic lenses, currently available outside the U.S., will enable older patients to focus at all distances. But for now, those well beyond their 40s may be better candidates for refractive lens exchange, as their natural lenses have stopped working for up-close tasks like reading.

Younger patients are more prone to retinal detachments with refractive lens exchange, another reason this procedure tends to be better suited for older adults.

Safety, Effectiveness, and Patient Preference

But perhaps most important to both doctors and patients are safety and effectiveness.

Among laser surgeries that remove corneal tissue, PRK boasts the best safety record. But compared with PRK, several studies suggest that phakic IOLs are even safer.

A Cochrane analysis of vision-correcting surgeries relied on an eye chart to assess the smallest line of print patients could read, first with glasses or contacts and again after surgery. In that comparison, patients treated with phakic IOLs were less likely to lose a line of vision and more likely to gain one compared with those who underwent laser vision-correcting surgery.

Yet, ophthalmologists have often reserved phakic IOLs only for patients ineligible for laser surgery.

That was how I first used phakic lenses in the military — until I started observing the amazing visual outcomes these patients experienced. Our studies concluded that phakic IOLs produced better day vision, night vision, and contrast sensitivity than laser surgery, a finding that has been consistently upheld in studies around the world.

However, one drawback is that phakic IOLs generally cost more than laser surgery, a key factor as most patients pay for refractive procedures out of pocket.

Still, for some, the higher price tag is a welcome tradeoff for the fact that phakic IOLs are the only removable vision-correcting procedure. If a novel surgery or upgrade becomes available, when age-related cataract removal is needed, or if a patient doesn’t like the result, a surgeon can simply remove the lenses.

For many of my patients, removability offers peace of mind. Others have a higher comfort level with LASIK or PRK because they are well-established, quite common treatments.

As ophthalmologists, it’s both our duty and privilege to offer a wide range of surgeries to suit patients’ preferences, and that’s well within our power given the caliber of strategies in our toolbox.

Although there are differences in their visual outcomes, I like to think of laser refractive surgeries as Corvettes and phakic IOLs as Ferraris — all wonderful vehicles despite some variations in their horsepower and performance.

With such a sleek fleet of solutions at our disposal to drive life-changing results, it’s an exciting time to be a refractive surgeon.

Scott D. Barnes, MD, is chief medical officer of STAAR Surgical, a leading developer, manufacturer, and marketer of implantable lenses and companion delivery systems for the eye, including EVO Visian ICL phakic intraocular lenses. An industry thought leader, Dr. Barnes has been involved in STAAR's medical education, professional affairs, and product development pathways since 2017, when he retired from the Army at the rank of Colonel. Before that, he was Chief of Ophthalmology Services at Womack Army Medical Center at Fort Bragg, North Carolina. In 2005 and 2011, respectively, Dr. Barnes served as a theater ophthalmology consultant in Iraq and Afghanistan.