Eyeworld

31 EW REFRACTIVE January 2017 Contact information Hafezi: farhad@hafezi.ch Kling: kling.sabine@gmail.com is probably related to proteoglycan crosslinking." Dr. Kling told EyeWorld the results explain why transepithelial crosslinking, which is comparable to the contact lens protocol in the study, is less effective in the clinic. "[Our results] suggest that using a longer irradiation time and hence allowing for longer oxygen diffusion could partially compensate for the reduced diffusion rate. Also, increas- ing oxygen pressure could increase the efficacy of transepithelial cross- linking," she said. This latter point, Dr. Kling said, could be achieved by saturating the air with oxygen or increasing the ambient pressure by performing the treatment within a pressure chamber. According to the study, differ- ences in crosslinking efficiency were seen among the protocols tested, but "we cannot draw a conclusion as to which is the minimal necessary in- crease of corneal stiffness to prevent keratoconus progression," Kling et al. wrote. "Currently, we speak of gen- eralized standard, accelerated, or transepithelial crosslinking proto- cols," Dr. Kling said. "In the future, I think a patient-specific crosslinking treatment will become available using either corneal thickness or topography data to determine the treatment parameters. We have learned that crosslinking consists of three main components: UV energy, riboflavin, and oxygen. Algorithms will need to be developed in order to determine the best parameter set for a given patient." "Some of these new concepts are fascinating, but my profession- al advice is we should take a little longer to validate them before we sell the machine to the patient," Dr. Hafezi said. "We have to make sure we have something that is effective." For now, Dr. Hafezi still prefers the Dresden protocol, although he does accelerate it to 10 minutes because there is a solid body of evi- dence supporting its efficacy. "I want to protect the technique because it works wonderfully," Dr. Hafezi said, noting that currently there is "total confusion" among his colleagues when it comes to the other, less established protocols. EW Reference 1. Kling S, et al. Increased biomechanical ef- ficacy of corneal cross-linking in thin corneas due to higher oxygen availability. J Refract Surg. 2015;31:840–846. Editors' note: Dr. Hafezi has financial interests with EMAGine (Zug, Switzer- land) and is co-inventor of the PCT/ CH2014/000075 application (UV light source). Dr. Kling has no financial interests related to her comments. NOW IN SINGLE-USE ! by DIAMATRIX IRIS SPECULUM 6.7mm near-circular dilation 30 day trial available, call 800.867.8081 No Pinching, Easily Rotates Visit our website Diamatrix.com for additional information

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