March 2020

REFRACTIVE

Research Highlight
Combined approach for managing keratoconus


by Maxine Lipner Senior Contributing Writer




Preoperative topography of a 20-year-old patient with keratoconus. For patients with keratoconus, a combined treatment approach can make it possible to not only stabilize vision but improve it.
Source: Judy Ku, MD, and David Rootman, MD

A combined treatment approach using corneal crosslinking, intracorneal ring segments, and phototherapeutic keratectomy could offer keratoconus patients something once thought to be an impossibility—corneal stability and improved visual acuity.
Research showed that a combined approach resulted in 13.5% of eyes achieving at least 20/25 uncorrected acuity and 96% achieving 20/40 or better best spectacle-corrected acuity, reported Guillermo Rocha, MD.1

Evolving technique

Dr. Rocha had been using all three methods independently in his practice. “In 1999, I started using Intacs [Addition Technology] for myopia, just for very low corrections,” he said, adding that it was not until around 2006, after reading reports by Joseph Colin, MD, that he began using intracorneal ring segments to tackle irregular astigmatism. Around 2010, he began using crosslinking to halt keratoconus progression.
However, he was not satisfied with this alone. “I thought, ‘Some patients have low correction. What if I added a correction with the laser, then did crosslinking?’” Dr. Rocha said, adding that it occurred to him that the patient might benefit from intracorneal ring segments at the same time. This was also based on the pioneering work of other colleagues.
Dr. Rocha’s idea of treating keratoconus with the laser continued to evolve. Already using the femtosecond laser to make channels for the intracorneal ring segments, it occurred to Dr. Rocha to shave off a little bit of the cone with the excimer laser. Dr. Rocha explained that since the epithelium in a keratoconic eye is thinnest at the apex of the cone, the rest of the epithelium could be used as a masking agent.
Combining these techniques, Dr. Rocha said physicians began to see not only halting of keratoconus progression but also significant vision improvement. “Many patients were not even wanting contact lenses and were wearing glasses in a minimal way,” Dr. Rocha said.

Studying combined results

A retrospective chart review was used to evaluate this combined procedure. The review included keratoconus patients with a central corneal thickness of at least 440 µm and a keratometry reading of less than 55 D, Dr. Rocha said.
“We found an improvement in the uncorrected visual acuity from 0.85 to 0.46 logMAR,” Dr. Rocha said, adding that corrected distance visual acuity improved from 0.19 to 0.11. The sphere in the manifest refraction improved from –4.42 to –2.94 D, and there was a reduction in cylinder of approximately 2.12 D. Those attaining uncorrected vision of at least 20/25 increased from 1.9% to 13.5%, and those who achieved 20/30 acuity went from 1.9% to 30.8%, he reported.
Investigators also saw a reduction in higher order aberrations. “Total higher order aberrations, coma, spherical aberration, and secondary astigmatism all showed statistically significant improvement,” Dr. Rocha said. “The only one that did not improve was trefoil.”
Dr. Rocha views this as a potential turning point for keratoconus patients. “I think that for years keratoconus patients have been used to hearing, ‘You have keratoconus, but at this point we don’t have anything to offer,’” he said. While it is now possible to stop keratoconus and improve vision, it’s important to assess the patient’s goals, Dr. Rocha stressed. Sometimes the goal is simply to stop progression of keratoconus, while others may want to do away with glasses and contact lenses if possible. In the latter case, it becomes a question of deciding how you are going to rehabilitate the patient’s vision. “I think that the idea is to think outside the box and see where we can get that patient,” Dr. Rocha said.
Overall, Dr. Rocha said it’s important to keep an open mind to new techniques, while simultaneously thinking about the benefit to the patient. “I think it’s worthwhile when we see that there are different ways of combining treatment to move forward and offer patients a better result than they were expecting,” he concluded.

About the doctor

Guillermo Rocha, MD
Professor of ophthalmology
Max Rady College of Medicine University of Manitoba
Winnipeg, Canada

Reference

1. Rocha G, et al. Combined phototherapeutic keratectomy, intracorneal ring segment implantation, and corneal collagen cross-linking in keratoconus management. Cornea. 2019;38:1233–1238.

Relevant disclosures

Rocha: Bausch + Lomb

Contact

Rocha: rochag@me.com

Combined approach for managing keratoconus Combined approach for managing keratoconus
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