Downloaded from http://journals.lww.com/retinajournal by BhDMf5ePHKbH4TTImqenVIdHfOa5cT8dHGzXgnGpJ6XvRkr7Gc+cwU7E4ulPxYH8 on 07/26/2020 Scan code to view VIDEO New Instruments TEMPORARY KERATOPROSTHESIS FOR PANORAMIC VIEWING SYSTEMS A New Design José Dalma-Weiszhausz, MD From the Retina Department, Asociación para Evitar la Ceguera en México IAP, Mexico City, Mexico. Surgical treatment of posterior segment pathology has greatly improved with the introduction of pars plana vitrectomy more than 40 years ago. This surgery requires transparent media through the cornea for optimal visualization. Corneal opacities can hinder adequate visualization, which compromises surgical and visual results. The development of a temporary keratoprosthesis (TKP) to temporarily replace the opaque cornea with a polymethyl methacrylate or silicone lens followed by the placement of a full- thickness corneal graft allows an excellent transoper- ative visualization of the posterior pole. 1,2 Although later versions of TKP allowed a wider field vision, they never allowed adequate visualization of the reti- nal periphery, the site of the most common pathology responsible for retinal detachments. 3 Therefore, one of the most common complications of this surgery is postoperative retinal detachment, often with severe proliferative vitreoretinopathy. 4,5 The results of modern vitrectomy have benefited enormously from the use of wide-angle viewing systems that allow a panoramic visualization of the fundus and a better approach to the pathology in the periphery of the retina. Description We designed a new TKP, modified from the wide- field Landers–Foulks TKP, to optimize the imaging capabilities of wide-angle visualization systems, ob- taining the broadest field of vision possible and pre- serving the excellent optical qualities needed for fine intraocular maneuvers. This TKP is made of poly(methyl methacrylate) and has a biconvex configuration with a diameter of 11 mm and a stem diameter of 7.2 mm, which adjusts to a 7-mm corneal trephine. The stem diameter may vary if a corneal graft of a different diameter is warranted. The total height of the stem is small (0.7 mm) to allow its use in a phakic or pseudophakic eye and to accommodate the posterior convex curvature. The anterior curvature was fixed at a radius of 8 mm. The posterior curvature was calculated at a radius between 12 mm and 19 mm, depending on the diameter of the stem and the total height; so, its total size does not interfere with intraocular maneuvers (Figures 1– 3). The diameter of the lens permits the use of a scleral- fixated ring to hold the contact lens of the wide-field vision system (AVI or Volk-type systems). This lens also works very well with the use of aerial systems (EIBOS: Erect Indirect Binaocular Ophthalmic System Haag Streit Surgical, Wedel, Germany; BIOM: Binocular Indirect Ophthalmo-microscopy, Oculus Optikgeräte GmbH, Wetzlar, Germany). Both provide excellent details and lighting while working under saline solution or air. The TKP is fixed to the cornea with 8-0 sutures placed through 4 or 6 small holes carved into the lens “wing” over the cornea. This allows a watertight seal over the keratectomy for a closed-system vitrectomy. We have used this device in several cases and have noticed an increased field of view of approximately 25° more than that using the wide-field Landers– Foulks TKP with the same wide-angle viewing sys- tems (see Video file 1, Supplemental Digital Content 1, http://links.lww.com/IAE/B214). This allows the viewing up to the ora serrata in most eyes. Unfortu- nately, the extra lens power of the proposed TKP does not allow for work in the vitreous cavity without a wide-angle viewing system under intraocular air or saline solution. Fig. 1. Diagram in cross-section of the TKP. R1, radius of curvature of the anterior surface; R2, radius of curvature of the posterior surface. None of the authors has any financial/conflicting interests to disclose. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s Web site (www.retinajournal.com). This project has been entirely self-funded. The patent for this device has been applied for in Mexico. Reprint requests: José Dalma-Weiszhausz, MD, Retina Depart- ment, Asociación para Evitar la Ceguera en México IAP, Av. Paseo de las Palmas 745-1202, Del. Miguel Hidalgo, Mexico City 11000, Mexico; e-mail: josedalma@gmail.com 1005 Copyright © by Ophthalmic Communications Society, Inc. Unauthorized reproduction of this article is prohibited.