JUN 11, 2019
Cornea/External Disease, Refractive Mgmt/Intervention
This study describes a novel device and technique for Epi-Bowman blunt keratectomy (EBK) that is designed to minimize postoperative pain, accelerate re-epithelialization and offer earlier visual recovery compared with the use of diluted ethanol in myopic photorefractive keratectomy (PRK).
This prospective, randomized contralateral eye study compared the outcomes of PRK using 2 different techniques for epithelial removal: EBK using a blunt epikeratome (Epi-Clear, Orca Surgical, Israel) or traditional 20% ethanol delamination of the corneal epithelium.
A total of 44 eyes of 22 patients were treated with PRK for bilateral myopia or myopic astigmatism, with 1 randomly-chosen eye of each patient undergoing EBK and the contralateral eye undergoing alcohol-assisted epithelial removal. Postoperative pain, epithelial healing, epithelial profile and visual outcomes were compared between the groups.
The mean period for re-epithelialization was 3.1 days in the EBK group versus 4.3 days in the ethanol group (P=0.017). The average postoperative pain scores over a 3-day period were 0.37for the EBK group and 0.82 for the ethanol group (P=0.043). On average, the mean epithelial defect sizes on postoperative day 3 were 1.61 and 2.25 mm2, respectively (P=0.034). There were no significant differences between groups in terms of postoperative residual spherical equivalent, UCVA or BCVA.
The ethanol group had a 9-mm zone of epithelial debridement whereas the EBK group had only an 8-mm zone of removal. This could represent a 27% increase in surface area of epithelial removal, potentially favoring results in the EBK group. The study authors attempted to mitigate this bias by stating that due to the manual nature of EBK epithelial removal, it was often larger than 8 mm in diameter, and in some cases even larger than 9 mm in diameter. Nevertheless, the 2 groups were not standardized in epithelial defect size from the start of the study.
The EBK group demonstrated smoother epithelial remodeling with less epithelial edema during the early postoperative period, which may correlate with the group’s faster visual recovery and could indicate less trauma than experienced by the other group. These findings are consistent with past studies suggesting that a smoother epithelial removal process, such as with the EBK device studied here, may minimize postoperative pain, accelerate re-epithelialization and offer earlier visual recovery compared with ethanol-assisted epithelial removal with PRK surgery.