CORNEAL CROSS-LINKING IN A PATIENT PRESENTING WITH KERATOGLOBUS, BLUE SCLERA, POSTERIOR LENTICONUS AND PROGRESSING CENTRAL ECTASIA.

 A 7 year old boy presented with known bilateral amblyopia and a gradually decreasing visual acuity. The best corrected visual acuity was found to be 05/10 OU (stable since age 2), with a known skiaskopic refraction of -12,00 sph/-5,00 x 180 cyl bilaterally. Slit-lamp examination revealed blue scleras and bilateral posterior lenticonus, with thin and protruding corneas of normal diameter. Slight apical scarring was present, without Vogt striae or Fleischer ring (persistent eye rubbing was reported by the parents). Intaocular pressure, axial length and fundus were unremarkable and so was the past medical history. The diagnosis of keratoglobus associated with central conical ectasia was established by Scheimpflung imaging, Placido topography and anterior segment OCT. Both eyes had substantial stromal thinning of the entire cornea, with a minimum central thickness of 260 μ and a Kmax of 78,9 dpt. As the patient reported gradually  deteriorating visual acuity and Placido topography indicated disease progress in the left eye, CXL was proposed. An epithelium off procedure was performed, using 0.1% hypoosmolar riboflavin in an accelerated protocol (5 minutes, 18 mW/cm2 ) with a total energy of 5,4 J/cm2.

 Full reepithelialization occured on the 9th post-operative day. A demarcation line was observed at 210 μ at 1,5 month after the procedure and no endothelial loss had occured. Corneal densitometry with Scheimpflung imaging revealed further increase of an already elevated backscatter indicating mild deterioration of a pre-existing apical scarring. The treatment was nevertheless considered successful as follow-up of 36 months showed stable keratometric values and best corrected visual acuity in the treated eye.