Retina Today - RETINA PEARLS: Achieving a Wide-angle View During Vitreous Surgery (January 2011)

[摘要] In this issue of Retina Today, Kazuaki Kadonosono, MD, PhD, discusses his surgical experienceachieving visualization of the retinal fundus during vitrectomy with the Resight 700 fundusviewing system (Carl Zeiss Meditec AG, Jena, Germany).We extend an invitation to readers to submit pearls for publication in Retina Today. Pleasesend submissions for consideration to Ingrid U. Scott, MD, MPH ([e-mail]); or DeanEliott, MD ([e-mail]). We look forward to hearing from you.—Dean Eliott, MD; and Ingrid U. Scott, MD, MPHWhat is the key to successful vitreous surgery?No single answer would be acceptableto every surgeon. However, it is afact that a clear view of the retinal fundusduring surgery is one key to a successful vitrectomy. Therecently developed wide-angle viewing microscope system,the Resight 700 (Carl Zeiss Meditec), offers several advantages over earlierwidefield-viewing systems, as this article describes.MECHANISMS OF WIDE-ANGLEVIEWING SYSTEMSVitreous surgery can be facilitated by indirect viewingsystems that provide surgeons with a wide-angle view ofthe fundus.1-3 Although the image is sufficiently widefield with these devices, it is inverted, which can be confusing,especially when surgeons are performing complexmaneuvers. The stereoscopic diagonal inverter (SDI),originally introduced to change the optics during vitreoussurgery, made the wide-angle field of the panfunduscopepossible.1Wide-angle viewing systems consist of two components:an indirect ophthalmoscopic lens system and astereo reinverter system that reinverts the image. Thefield of view depends primarily on the distance betweenthe indirect-noncontact lens surface of the operatingmicroscope and the corneal surface. As the noncontactlens approaches the cornea, the observed field grows larger. Anotherdeterminant of theobserved field is therefractive power ofthe lens: Thestronger the powerof lens, the larger thefield of the fundusthat can beobserved.Focusing the operatingmicroscope isas important as thevisual field because itqualifies the image.The images obtainedby noncontact lensesare inferior to thoseobtained by contactlenses, and the resolutionof fundusimages by wide-angleviewing systems hasnot been very good.Focusing the binocularindirect ophthalmoscope(BIOM;Oculus, Lynnwood,WA), which has beenthe most popularwide-angle viewing system, is complicated, requiring most surgeons tospend a great deal of time learning how to use theBIOM system.There are two key elements to focusing with theBIOM system: (1) maintaining a suitable distancebetween the indirect lens and the corneal surface, and(2) maintaining the optimal distance between theheight of the operating microscope and the corneal surface.This means that surgeons have to control both theindirect lens and the operating microscope at the sametime in order to obtain high-resolution images of thefundus (Figure 1B).RESIGHT FOCUSING SYSTEMThe Resight wide-angle viewing system has a uniquefocusing system. The Resight is equipped with an innerfocusing system that allows the reduction lens set insidethe microscope to be moved automatically. Surgeons canobtain clearer images by controlling this inner focus systemalone (Figure 1C). The focusing system has been simplifiedeven more in the Resight operating microscope system than in conventional operating microscopes.This technology can hold two lenses, a 128 D lens forwide-angle viewing and a 60 D lens for magnifyingimages of the posterior pole. These lenses provide clearfundus images with minimal distortion. The fundusimage is inverted automatically by Resight’sInvertertube E. Users can also adjust the focus with thefootswitch of the microscope through an internal focusingsystem.The following are several case reports illustrating theutility of this wide-angle viewing system.Case 1. A 67-year-old man who had undergonecataract surgery and IOL implantation 7 years earlierexperienced sudden visual loss. The patient’s IOL haddislocated posteriorly. Vitrectomy was performed toremove the IOL and fixate a new one to the sclera.When perfluorocarbon liquid (PFCL) was injected intothe vitreous cavity, the IOL floated on the PFCL andgradually approached the anterior segment. The Resightwide-angle viewing operating microscope made it possibleto obtain a wide view and clear image of the IOLduring surgery (Figure 2). As a result, there was littlepossibility of losing visualization of the floating IOL duringsurgery, and safe and successful rescue of the IOLwas performed. The IOL was sutured to the sclera, andthe patient’s vision improved.Case 2. Vitrectomy was performed to treat funnelshapedretinal detachment secondary to proliferative vitreoretinopathyin the right eye of a 56-year-old woman.Membrane resection was safely and effectively performedbimanually with forceps because the surgeon hadboth a clear image of the membrane and a wide-anglview of the fundus. After removing the membranes andperforming partial peripheral retinectomy, PFCL wasinjected into the eye and subsequently exchanged withsilicone oil. The PFCL was replaced with silicone oil because the oil afforded the surgeona clear image of the PFCL and theretina (Figure 3). The patient’s visionwas improved postoperatively, andthere were no complications. Surgicalcomplications such as retinal slippageand retention of drops of PFCL,which sometimes occur during siliconeoil exchange, did not occur.Case 3. The Resight was used toperform vitrectomy in a 57-year-oldpatient with a macular hole. Whenthe 60.00 D lens was used, the surgeoncould perform macular surgerywithout using the contact lens(Figure 4A). The patient’s internallimiting membrane was removed safely and effectivelyby staining with indocyanine green and using the wideangleviewing system alone (Figure 4B).CONCLUSIONThe Resight wide-angle viewing operating system hasseveral advantages over other operating systems. It facilitatesobtaining both high-resolution images and a widefieldview of the fundus at the same time. This technologycan provide great benefits when performing macularsurgery to treat challenging cases.Kazuaki Kadonosono, MD, PhD, is Professorand Chairman of the Department ofOphthalmology at Yokohama City UniversityMedical Center, Japan. He states that he has nofinancial relationship to disclose. Dr.Kadonosono may be reached by phone at [phone];or via e-mail at [e-mail] Eliott, MD, Dean Eliott, MD, is Associate Director ofthe Retina Service, Massachusetts Eye and Ear Infirmary,Harvard Medical School, and is a Retina Today EditorialBoard member. He may be reached by phone: [phone]; fax: [phone]; or e-mail:[e-mail] U. Scott, MD, MPH, is Professor of Ophthalmologyand Public Health Sciences, Penn State College of Medicine,Department of Ophthalmology, and is a Retina TodayEditorial Board member. She may be reached by phone: [phone]; fax: [phone]; or e-mail: [e-mail] M. A binocular indirect ophthalmoscope (BIOM) for non-contact wide-angle vitreoussurgery. Graefes Arch Clin Exp Ophthalmol. 1987;225(1):13-15. Landers MB, Peyman GA, Wessels IF, et al. A new, non-contact wide field viewing systemfor vitreous surgery. Am J Ophthalmol. 2003;136(1):199-201. Horiguchi M, Kojima Y, Shimada Y. New system for fiberoptic-free bimanual vitreous surgery.Arch Ophthalmol . 2002;120:491-494.

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