Eyeworld

137 EW REFRACTIVE March 2018 a much more highly concentrated solution than the one described in the classic Dresden protocol. Once VibeX was put in the channels, higher fluence (30 mW/cm 2 for total 7.2 joules delivered) was applied, and corneal crosslinking could take place in the ex vivo model. Dr. Kanellopoulos obtained OCT images of the post-Intacs-like implantation. Complications associated with ICRS include false channels, shal- low placement, significant opaque material deposition outside the seg- ments (resulting in vision problems), corneal melt, eroding segments, and segment extrusion. If left untreated, these can result in infectious kera- titis, which can be difficult to treat since infections in the setting of foreign bodies such as PMMA Intacs segments can be even more difficult to manage. Segments in a false chan- nel can result in complications like extrusion and chamber perforation. Extruded segments need to be re- moved immediately and the channel irrigated with antibiotics. Perfora- tions into the anterior chamber are treated according to the size of the perforation. The physician needs to withdraw the segment and place an air bubble into the anterior chamber to tamponade the perforation from the inside, remove the segment, and suture the entry incision. Bad experience In a previous prospective, non-ran- domized case series that involved ICRS implantation in 20 eyes of 15 keratoconus patients performed by Dr. Kanellopoulos and his team, many of the above complications were evident. 1 While the ICRS implantations were notable for their ability to improve visual acuity and short-term visual rehabilitation in patients with moderate to advanced keratoconus who were intolerant to contact lens and spectacle correc- tion, in this limited case series, it also raised significant concerns about the actual stability of the ring segments in the cornea and the potential risks of intrastromal ring segment corneal extrusion and infection. Dr. Kanellopoulos pro- posed permanent or longer-term suturing of the axial incision site as well as the possibility of intraopera- tive anchoring of the ring segments between them, with suturing if nec- essary, to help reduce their migra- tion or their overlapping within the channel. He also suggested placing the incision site at 12 o'clock to reduce movement and the implanta- tion of thinner segments. In the current study, Dr. Kanel- lopoulos addressed the possibility of achieving a more stable, more compatible long-term implantation of ICRS using segments made of a biocompatible material, such as porcine cornea, instead of PMMA. "Migration and extrusion of porcine corneal segments in a procedure using CXL are possibly less likely to occur," he said. "We have reported some of the hardships in intracor- neal ring segment surgery, which in our clinic experience involved mainly extrusions, melts, and infec- tions. The efficacy of the procedure was satisfactory, but the long-term stability of PMMA Intacs in the cor- nea proved to be suboptimal. We are willing to study this novel technique further and apply for the possibility of clinical trials." EW References 1. Kanellopoulos AJ, et al. Modified intracor- neal ring segment implantations (INTACS) for the management of moderate to advanced keratoconus: efficacy and complications. Cornea. 2006;25:29–33. 2. Mitchell BM, et al. Post intrastromal corneal ring segments insertion complicated by Candi- da parapsilosis keratitis. Clin Ophthalmol. 2013;7:443–8. 3. Chan CC, et al. Effect of inferior-segment Intacs with and without C3-R on keratoconus. J Cataract Refract Surg. 2007;33:75–80. Editors' note: Dr. Kanellopoulos has no financial interests related to his comments. Contact information Kanellopoulos: ajkmd@mac.com Figure 3. Ring insertion (left); ring inserted (middle); UVA CXL application (right) Figure 4. OCT corneal sections Source (all): A. John Kanellopoulos, MD

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