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EW CORNEA 56 October 2014 by Michelle Dalton EyeWorld Contributing Writer Combining CXL and CK Details of the procedure Dr. Rubinfeld uses an intraoperative keratometer to ensure he is provid- ing the desired results in real time, and based on serial Pentacam (Oculus, Wetzlar, Germany) images, may take the patient back to the OR for additional spots. He then performs CXL the next day with a proprietary, highly effective epi-on technique. Although most patients would show regression based on Pentacam images in the first few months after the sequential procedures, the changes remained unnoticed by patients, who still claim good visual acuity, which is borne out in their exams as well, Dr. Rubinfeld said. The nomogram for treating irregular astigmatism with CK has evolved in the study. Saying he "worked his way up in the proto- cols" of the CXLUSA group, Dr. Rubinfeld initially made superior CK spots far from the visual axis to steepen the overly flat superior area of the patient's cornea "to make it more uniform." Once he realized the superior spots worked, Dr. Rubinfeld added inferior spots "in the hopes that they would flatten the overly steep areas." By modifying the number and location of the spots, Dr. Rubinfeld creates more homogenous corneas (in the sense they are less irregular), profiles, he said, adding Arthur Cummings, FRCSEd, had previous- ly found that thermokeratoplasty using another modality subsequent- ly followed by CXL "resulted in patients with longer-lasting results than those where he performed thermokeratoplasty and crosslinking simultaneously." As a result of Dr. Cummings' outcomes and cumulative CXLUSA study results, the procedure of choice for Dr. Rubinfeld for patients with moderate to advanced vision loss from ectasia or keratoconus is CK followed by CXL the next day. To date, there does not seem to be a max K that is too steep to treat, he said. CK is not without its limits, however. When used as a standalone refractive procedure for the treat- ment of presbyopia, regression was a common occurrence that led to the procedure becoming less popular as a first-line treatment option for presbyopia. "CK is a great procedure and even better if you can get the effect to last longer," Dr. Rubinfeld said. By placing "just a few CK spots in the right places" in patients with keratoconus, he has found a "huge positive effect in regularizing the corneal shape." Combining procedures Numerous studies in the literature confirm the ability of CXL to stab - lize the cornea and prevent further vision loss in patients with keratoco- nus. But oftentimes, these patients are displeased they had a procedure but didn't gain any vision. "Our patients typically don't understand that maintaining the same visual acuity is considered a victory," Dr. Rubinfeld said. Combining CXL with a refractive procedure, however, has been successful in markedly improving vision in some patients, he added. "For example, conductive kerato- plasty (CK) is a noninvasive option that does not require any kind of incision and has an excellent safety profile. Combining these 2 non invasive procedures has yielded very encouraging results and restored the ability to drive and function for many of our patients." If a patient presents to one of the study sites with just keratoconus and no vision loss, "CXL alone is the way to go," Dr. Rubinfeld said. But "if the best corrected vision and/or the quality of vision is not good, we have started offering CK plus crosslinking under one of our ap - proved protocols, and we have been really encouraged by the results." Both procedures are noninva- sive, involve no epithelial removal or incisions, and have very low risk C orneal collagen cross- linking (CXL) for the treatment of keratoco- nus and ectasia has been approved throughout the European Union since 2006 but has yet to receive approval in the U.S. In 2009, a group of U.S. corneal specialists formed a non-commer- cial, physician-sponsored research group, CXLUSA, to investigate and further refine the procedure with the approval of several Investigational Review Boards. Roy Rubinfeld, MD, a CXLUSA group member, noted that the Eye Bank Association of America and Doyle Stulting, MD, PhD, estimate that more than 40% of the corneal transplants in the U.S. could be avoided if crosslinking were approved in the U.S. "For patients with keratoconus, the usual objective of CXL is not to get rid of glasses or contacts, but rather to stop [patients] from losing their vision due to progressively worsening irregular astigmatism," said Dr. Rubinfeld, in practice at Re:Vision – Roy S. Rubinfeld, MD, Rockville, Md., and Fairfax, Va. Dr. Rubinfeld is also a faculty member at Georgetown University Medical Center and Washington Hospital Center, Washington, D.C. "Our most recent developments and protocols now attempt to take people who have poor vision and restore some of the vision that was lost as a result of ectasia or keratoconus." Preoperative corneal scan of keratoconus patient (middle image) with marked inferior/superior asymmetry. The image on the left is immediately after CK with a new nomogram, and on the right the difference map is visible. Source (all): Roy Rubinfeld, MD Graph showing long-term improvement from CK plus crosslinking. Visual improvement was found to be greater in patients with worse preoperative best corrected vision.