CXL effects remain generally stable 10 years post-treatment

Steven Greenstein, MD, reports on results of epi-off corneal collagen cross-linking treatment in keratoconus and ectasia patients 10 years after undergoing laser refractive surgery.

Reviewed by Steven A. Greenstein, MD

Epi-off corneal collagen cross-linking (CXL) treatment, which received FDA approval in 2016 for treating progressive keratoconus and ectasia that develops after refractive surgery, appears to remain stable for the majority of patients 10 years postoperatively, according to Steven Greenstein, MD, who is with the Cornea and Laser Eye Institute in Teaneck, NJ.

Greenstein and colleagues conducted a single-center study that was part of the phase III pivotal US trial of corneal crosslinking in progressive keratoconus and ectasia (Glaukos) to determine how well the procedure fared over time.

Peter Hersh, MD, director of the Cornea and Laser Eye Institute, was medical monitor of the original multicenter clinical trials.

The primary outcome indicator was change in maximum keratometry (Kmax) and, secondarily, changes in the logarithm of the minimum angle of resolution (logMAR) uncorrected and best-corrected visual acuity (UCVA and BCVA, respectively), and compared with preoperatively.

Thirty eyes of 16 patients were included in the analysis. Of these, 15 had keratoconus and 15 had ectasia after laser refractive surgery.

Progression was defined as steepening of Kmax by 2 diopters or more, a decrease of the logMAR visual acuity by 2 lines or more, and by progression seen on the Belin ABCD progression display, he recounted.

Results
Greenstein reported that the patients treated for keratoconus did especially well, with 86.7% having stable topography 10 years after CXL. Indeed, 26.7% of these patients had an improvement of 2 diopters or greater flattening of the cornea.

Among the patients with ectasia, 66.7% had stable topography at 10 years postoperatively, and 53.3% of these patients improved with 2 or more diopters of flattening after CXL. Dr Greenstein noted that this topography analysis included 10 eyes (4 with keratoconus, 6 with ectasia) that underwent topography-altering surgery after the CXL procedure and before the 10-year examination.

Regarding the visual acuity, 60% of eyes with keratoconus remained unchanged and 20% gained 2 or more lines of logMAR UCVA; the BCVA findings showed that 60% remained stable and 40% had a 2-line or greater improvement.Among the patients treated for ectasia, 21.4% remained stable and 21.4% had a gain in of 2 or more lines of UCVA logMAR vision; the BCVA remained stable in 50%, and 21.4% had a 2-line or greater gain in VA.

The topography analysis showed that 60% of keratoconus patients remained stable and 26.7% had a 2-diopter or greater flattening of the cornea. Among the ectasia patients, 13.3% remained stable and 53.3% had a 2-diopter or greater flattening.

The Belin ABCD progression display found that 93.3% of keratoconus patients and 64.3% of the ectasia patients had no progression of the anterior or posterior corneal curvature.

“In general, CXL appears to remain stable 10 years after treatment,” the investigators concluded. “The topography was stable in 77% of the entire cohort, in 87% of the keratoconic eyes, and in 67% of the ectasia eyes. The BCVA also was stables in 88% of the entire cohort, in 100% of the keratoconic eyes, and in 71.4% of the ectasia eyes.”

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Steven Greenstein, MD
E: sgreenstein@vision-institute.com
This article is adapted from Greenstein’s presentation at the American Society of Cataract and Refractive Surgery 2021 annual meeting. He is a consultant to Glaukos.