Eyeworld

EW FEATURE January 2011 53 Complex conditions have led surgeons to adapt their use of viscoelastics in order to maximize the ben- efits and reduce risks A growing number and more types of surgical viscoelastics have given ophthalmic surgeons more options in protect- ing patients during standard anterior segment procedures. However, pa- tients with complex conditions have led surgeons to modify their selec- tion and use of these ophthalmic viscosurgical devices (OVDs). Viscoelastics have common and accepted protective roles during cataract surgery, refractive lens sur- gery, phakic IOL insertion and ex- plantation, IOL exchange, cases of posterior capsule breakage, anterior vitrectomy, and corneal transplanta- tions. Common roles for dispersive viscoelastic agents include endothe- lial protection, epithelial coating, and lubrication for IOL injectors. Cohesive agents are generally used to provide space maintenance, flat- ten the anterior capsule during cap- sulorhexis creation, and inflate the capsular bag for IOL insertion. Visco-adaptive agents have shown efficacy among patients with the frequent complication of Intra- operative Floppy Iris Syndrome (IFIS), where they are used to se- quester the iris tissue, for visco-my- driasis. "For a routine cataract surgery, using a dispersive plus a cohesive provides me the most versatility and best results," said Uday Devgan, M.D., in private practice, Devgan Eye Surgery, Los Angeles, Calif. Similarly, Thomas A. Oetting, M.D., professor, clinical ophthalmol- ogy, and director, residency pro- gram, University of Iowa commonly utilizes two types of viscoelastics as part of the Arshinoff shell technique in cataract surgery. This approach entails first plac- ing the viscous dispersive Viscoat (3% sodium hyaluronate, 4% chon- droitin sulfate, Alcon, Fort Worth, Texas) and then placing a cohesive such as Provisc (sodium hyaluronate, Alcon) or Healon5 (sodium hyaluronate 2.3%, Abbott Medical Optics, AMO, Santa Ana, Calif.) just over the lens to push the dispersive anterior onto the corneal endothelium. "As soon as you start the phaco all of the cohesive is gone (with the vacuum of the tip) but the dispersive remains to protect the endothe- lium," Dr. Oetting said. "In my hands, at least, no other technique protects the endothelium better." Adjusting for complications But beyond standard cases of cataract removal surgeons have found a need to modify their use of viscoelastics. For instance, in the un- usual cases of adults with white cataracts and in pediatric cataract cases some aspects of viscoelastic usage are critically important, ac- cording to Kevin M. Miller, M.D., Kolokotrones Professor of Clinical Ophthalmology, Jules Stein Eye In- stitute, David Geffen School of Med- icine, University of California, Los Angeles. In dense cataract cases, Dr Miller moves from his standard co- hesive/dispersive agent DisCoVisc (hyaluronic acid 1.6%–chrondroitin sulfate 4%, Alcon) to Viscoat, which has improved dispersive properties. Dr. Miller fills the anterior chamber completely with the viscoelastic to help maintain intraocular pressure before performing the anterior cap- sulotomy and capsulorhexis. "In these special cases it is important to flatten the anterior surface of the cornea," said Dr. Miller, about white cataract and pediatric cataract cases. Switching when needed William B. Trattler, M.D., director of Cornea, Center for Excellence in Eye Care, Miami, Fla., and volunteer assistant professor of ophthalmol- ogy, Bascom Palmer Eye Institute, also switches from his standard vis- coelastic, DisCoVisc, in many non- cataract surgeries. For example, in corneal transplant and ruptured globe cases Dr. Trattler has found Healon5 provides dependable space maintenance. "So even when there is an opening, the viscoelastic can stay in place and help keep the con- tents of the eye in its proper posi- tion," Dr. Trattler said. Additionally, Healon5's space maintaining qualities in cases of ruptured globes and corneal lacera- tions leaves room for Dr. Trattler to pass a suture without worrying about the iris trying to move for- ward into the wound. Rosa Braga-Mele, M.D., MEd, associate professor, University of Toronto, director, Cataract Unit, Mt. Sinai Hospital, Toronto also switches from Healon GV (1.4% sodium hyaluronate, AMO) in normal eyes to Healon5 in complex cases. The viscoadaptive agent's good space-cre- ating and -maintaining properties are especially important in cases with small pupils, IFIS or shallow chambers, according to Dr. Braga- Mele. However, Dr. Braga-Mele con- tinues with Healon GV and the soft shell technique in dense nucleus cases. Viscos important for corneas In patients with corneal problems, Dr. Braga-Mele has found benefits in dispersive viscoelastics such as Vis- coat. In corneas with Fuch's endothe- lial dystrophy, Stanley J. Berke, M.D., associate clinical professor, Ophthalmology & Visual Sciences, Albert Einstein College of Medicine, has found that liberal use of the vis- coelastics is effective in protecting damaged corneas. "I will stop during the procedure to add more viscoelac- tic—usually Amvisc Plus (Bausch & Lomb, Rochester, N.Y.)—to protect the corneal endothelium," Dr. Berke said. Another type of cataract case in need of special viscoelastic protec- tion, said Dr. Oetting, is when the vitreous is looming. He uses Viscoat (or Ocucoat [Bausch & Lomb Surgi- cal], with some reservations due its lack of viscousness) in these cases because these patients tend to retain some OVD and the smaller mole- cules of dispersives like Viscoat are less likely to create a pressure spike. "Also the dispersive is better for sealing off an area as dispersive OVD likes to stick to other things like cap- sule, iris, or the cornea; whereas, co- hesive likes to stick to itself and does not seal off areas well," Dr. Oetting said. The same advantages are pro- vided by dispersives when iris sutur- ing IOLs, scleral suturing IOLs, and when placing secondary IOLs, he said. Viscoelastic usage also is chang- ing in another type of nontradi- tional cataract patient. Dr. Devgan, chief of ophthalmology, Olive View UCLA Medical Center, and associate clinical professor, Jules Stein Eye In- stitute, UCLA School of Medicine, said that as he has moved toward micro-incisional cataract surgery (MICS) using incisions from 1.8mm to 2.2 mm less fluid goes through the eye, less leakage occurs from the incisions, and more viscoelastic is re- tained during surgery. "This can allow surgeons to use less viscoelas- tic during the case," Dr. Devgan said. EW Editors' note: Drs. Oetting and Berke have no financial relationships with any companies mentioned in this arti- cle. Dr. Devgan has financial interests with AMO, B&L, and Hoya; a speaker for Alcon. Dr. Miller has financial in- terests with Alcon. Dr. Trattler has fi- nancial interests with AMO. Dr. Braga-Mele has financial interests with Alcon, AMO and B&L. Contact information Oetting: 319-384-9958, thomas- oetting@uiowa.edu Devgan: 800-337-1969, devgan@gmail.com Miller: 310-206-9951, kmiller@ucla.edu Trattler: 305-598-2020, wtrattler@gmail.com Braga-Mele: 416-462-0393, rbragamele@rogers.com Berke: 516-593-7709, sberke@ocli.net by Rich Daly EyeWorld Contributing Editor Viscoelastic usage varies with conditions EyeWorld Factoid About 55% of ophthalmic practices now have optometrists on staff, compared to 47% in 2007 Source: American Academy of Opthalmology and American Academy of Ophthalmic Executives, 2009

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