PACK-CXL with riboflavin, rose bengal shows efficacy against Acanthamoeba keratitis
Click Here to Manage Email Alerts
VIENNA — Using PACK cross-linking with two chromophores, riboflavin and rose bengal, in the same session showed efficacy in the treatment of Acanthamoeba keratitis, according to a poster presentation.
“In the last few years, the efficacy of riboflavin-mediated cross-linking for infections has increased significantly because we learned how to increase the total energy (fluence). But Acanthamoeba remains an unresolved mystery because this parasite is so extremely resistant,” Farhad Hafezi, MD, PhD, FARVO, said at the European Society of Cataract and Refractive Surgeons meeting.
Rose bengal has shown some efficacy as a chromophore in the treatment of Acanthamoeba keratitis but has lower penetration depth than riboflavin, and the effect is limited to the first 150 µm of corneal depth. After studying riboflavin and rose bengal absorption spectra, Hafezi realized that they do not overlap, leading to the possibility of using both chromophores in the same session.
“We are currently doing laboratory research on this same-session combination of riboflavin with UV irradiation and rose bengal with green light irradiation, in the same cornea, a few minutes apart,” Hafezi said.
This procedure was also used compassionately in one patient, a 44-year-old contact lens wearer with constant pain and photophobia because of PCR-confirmed Acanthamoeba keratitis that did not respond to any conventional treatment for more than 12 months.
“We received ethical clearance for compassionate use and treated the patient with this same-session combined procedure. We repeated the treatment twice, after 8 and 16 weeks. Eight months later, confocal microscopy showed no sign of Acanthamoeba,” Hafezi said.
Recently, the patient was able to undergo penetrating keratoplasty and no longer has pain or photophobia. This is only a case report for now, Hafezi said, but it is encouraging, and this same-session combined procedure might evolve into a treatment modality for Acanthamoeba keratitis.
Collapse
Hafezi F, et al. Successfully combining riboflavin/UV-A and rose bengal/green light PACK cross-linking in Acanthamoeba keratitis. Presented at: European Society of Cataract and Refractive Surgeons meeting; Sept. 8-12, 2023; Vienna.
Read more about
Click Here to Manage Email Alerts