Combination of PRK, cross-linking shows good results over 4 years

Issue: April 10, 2019

ATHENS, Greece — A combination of PRK and accelerated corneal cross-linking, called PRK Xtra, may be a way to perform refractive surgery in eyes with suspicious corneal topography, according to a study presented at the European Society of Cataract and Refractive Surgeons Winter Meeting.

“Targeted undercorrection by 10% of preoperative [spherical equivalent] refraction resulted in effectively achieving postoperative refraction within ±0.5 D,” Michael Grentzelos, MD, said.

Asymmetric bow tie patterns, skewed radial axis and/or inferior steepening of the axis by 1 D or more should alert the surgeon that the patient might be at risk for developing ectasia after refractive surgery. However, the combination with cross-linking might give the cornea the extra strength required to undergo the procedure safely.

“If we can successfully combine CXL with refractive surgery in keratoconic patients, why not combine refractive surgery with CXL in refractive patients in order to prevent iatrogenic ectasia, particularly in patients with suspicious topography?” Grentzelos said.

The group of George Kymionis, MD, at the University of Crete performed PRK Xtra in a group of 10 eyes of five patients with suspicious corneal topography and followed them for 4 years. The average age was 29 years, the average spherical equivalent was –2.74 D, and the average corneal thickness was 508 µm.

PRK was performed with mechanical removal of the epithelium and intraoperative instillation of mitomycin C. CXL was performed with an accelerated procedure for 5 minutes with an irradiance of 18 mW/cm².

Taking into account the hyperopic shift that follows CXL, target refraction was reduced by 10% in comparison with cycloplegic refraction in nine of the eyes.

“At the last visit, nine eyes had [spherical equivalent] within ±0.5 D, while the eye that was not undercorrected had an overcorrection of +1.25 D,” Grentzelos said.

None of the eyes lost lines of best corrected visual acuity, and two eyes gained one line. The average central depth of the demarcation line was 144.9 µm.

“We need a larger case series to better evaluate the outcomes of this combined procedure. However, we were able to demonstrate that in this series the procedure was safe, leading to stable results over 4 years,” Grentzelos said.

Reference:

Kontadakis G, et al. Treatment of myopia and astigmatism in eyes with suspicious topography with PRK followed by accelerated CXL: PRK-Xtra. Presented at: ESCRS Winter Meeting; Feb. 15-17, 2019; Athens, Greece.

Disclosure: Grentzelos reports no relevant financial disclosures.