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Study finds ‘epi-cross-linking’ preferable to manual scraping in mild keratoconus
The new procedure reduces pain, enhances correction of spherical equivalent and avoids damaging Bowman’s membrane.
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For epithelial removal in cases of mild keratoconus, “epi-cross-linking” appears to be the technique of choice, according to a study that compared standard manual scraping to an epikeratome blade.
Researchers evaluated the use of the Epi-K blade by Moria for removing the epithelium.
“We found there was faster visual and pain recovery with epi-cross-linking — an impressive 20% and 40%, respectively,” principal investigator L. Felipe Vejarano, MD, director of the anterior segment fellowship program at Fundacion Oftalmologica Vejarano in Popayán, Colombia, said. “The epi-cross-linking also compensated more for spheric and astigmatic defects: two-thirds of spherical equivalent instead of one-third with the manual technique.”
Vejarano, who uses the term “epi-cross-linking,” undertook the study because epithelium removal has always been problematic for him.
L. Felipe Vejarano
“I thought that by removing epithelium with the Epi-K, the procedure would be easier and allow for better patient recovery in terms of pain, time of total epithelialization and visual acuity,” he said.
On the other hand, Vejarano was slightly hesitant that the suction from the ring might worsen the ectasia but took comfort in the fact that he was causing a stiffening of the cornea.
“Epi-cross-linking is easier to perform than manual scraping, even if the surgeon has never used an Epi-K before,” Vejarano told Ocular Surgery News. “And it has no additional risks or complications compared with standard Epi-K.”
Exact and precise irradiation areas are also predictable and reproducible for any surgeon, according to Vejarano.
The study consisted of two groups of patients. The manual scraping cohort included 35 eyes of 27 patients (average age 23.5 years), 19 of whom had monocular and eight who had binocular treatment. The epi-cross-linking group included 19 eyes of 12 patients (average age 22.3 years), five of whom had monocular and seven of whom had binocular treatments.
Both groups were followed for an average of 12 months.
“When I started the study, I thought that pain recovery would be better and that there would be fewer patient complaints because of the exact epithelium removal achieved with the Epi-K,” said Vejarano, who presented his findings at the 2013 American Society of Cataract and Refractive Surgery meeting. “However, I never imagined the 79% improvement in uncorrected visual acuity, compared to a 40% improvement with the manual technique.”
Vejarano suspects that the impressive UCVA results are due in part to avoiding any damage to Bowman’s membrane.
“Mild damage of the membrane is always a distinct possibility when you manually scratch the epithelium,” Vejarano said.
Improvement in UCVA, coupled with the significant decrease in spheric and astigmatic defects, affords the patient “a better independence of glasses,” Vejarano said. “The cornea is also better preserved for any future custom PRK. With less defect, the patient will have a better prognosis to receive a refractive surgery, provide a better quality of life and, of course, reap the benefits of any laser vision correction like any normal person without ectasia would.”
To increase the efficacy of treatment with the Epi-K, Vejarano recommends using a large cut ring with no stops for a free-cap smoothing technique and to create larger epithelial flaps.
“Do not be afraid of steep corneas,” he said. “The results are the same and the smoothness of the corneal bed is amazing when compared with any manual procedure.”
The obtained angle on the edge of the epithelium with epi-cross-linking may also help to attain even faster visual recovery. – by Bob Kronemyer