Eyeworld

118 | EYEWORLD | APRIL 2019 C ORNEA by Stefanie Petrou Binder, MD EyeWorld Contributing Writer PRESENTATION SPOTLIGHT A new study found that the choroid in eyes of patients with keratoconus is significantly thicker than those of healthy controls. Increased choroidal thickness is less evident in individuals 45 years or older, when keratoconus is thought to have reached stability, according to Jorge Ruiz-Medrano, MD, who reported the outcomes of his study at the 36th Congress of the European Society of Cataract and Refractive Surgeons (ESCRS). Swept source OCT of the fovea The prospective, cross-sectional study included 102 eyes from 51 keratoconus patients and used swept source OCT to determine whether patients suffering from different stages of keratoconus present with alterations of their choroidal thick- ness profile. The study included eyes with both a clinical and topographic diagnosis of kerato- conus, only including high quality images. Eyes with ocular trauma, retinal diseases, any eye tumor pathology, and an axial length in excess of 26 mm were excluded. Examinations were conducted in both eyes to avoid bias and comprised Pentacam (Oculus) images to determine the Amsler-Krumeich clas- sification for keratoconus, IOLMaster 500 (Carl Zeiss Meditec) measurements for axial length, Triton swept source OCT (Topcon) to measure choroidal thickness, as well as comparisons to age- and gender-matched healthy controls. The Macular choroidal thickening in keratoconus patients Parker said. "It's not just that they're riddled with scars, but also the shape is totally irregular." While the temptation is to replace the whole structure, investigators found that just replacing the back 5% of the cornea dramatically improved the shape in every case. "If you can improve the shape just by fixing the back, you can have a much smaller surgery and you expose the patient to few- er risks," he said. If the endothelium goes bad, the cornea starts to swell, and while many times the cornea looks soggy, sometimes that swelling is not obvious. "Probably when the cornea swells and it has lost its structural support it starts to bulge," he said. "Probably after DMEK, the new cells reverse that swelling; when you fix the swelling, those changes seem to be at least partially reversible." Investigators were concerned that irregulari- ties on the back of the RK from scarred corneas would interfere with the graft sticking and were surprised to find this was not the case. "The detachment rate was exactly the same in all of the previous reports so that didn't seem to be a con- traindication for this operation," Dr. Parker said. When it came to best corrected spectacle acu- ity, 80% attained visual acuity of 20/40 or better by the 6-month postoperative mark. Dr. Parker hopes that physicians come away from the study understanding that abnormalities in shape or bulging of the cornea from RK or Fuchs' dystrophy do not necessarily require a full-thickness corneal transplant. "They can be dramatically improved just by replacing the back of the cornea," he said. An image obtained with the Deep Range Imaging OCT-1 Atlantis Source: Topcon continued from page 116 continued on page 120 About the doctor Jorge Ruiz-Medrano, MD Jules Gonin Eye Hospital Lausanne, Switzerland

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