EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/376249
EW FEATURE 60 by Rich Daly EyeWorld Contributing Writer Phaco and corneal comorbidities September 2014 AT A GLANCE • The visually disabling nature of guttae is one reason for the combination of cataract and cornea procedures. • Hydrophobic acrylic lenses are the choice of many surgeons in these cases. • Time and experience are needed in these cases. Questions remain in combined cataract/cornea cases The density of the guttae is the deciding factor for whether to perform a triple DMEK procedure for Mark A. Terry, MD, director of corneal services, Devers Eye Institute, and professor of clinical ophthalmology, Oregon Health & Science University, Portland, Ore. He explained: "If they have symp- toms but the guttae are only 1 or 2+, I have the referring surgeon do just cataract surgery. If they have central guttae that are confluent (best seen as an 'oily' posterior layer by red reflex or by retinoscopy), I will do a combined DMEK with phaco. Certainly if they have symptoms or signs of frank stromal edema, a DMEK triple procedure should be done." Kashif Baig, MD, FRCSC, assis- tant professor, University of Ottawa, also said his decision to operate is based more so on symptoms, such as glare, halos, declining vision, pain from erosions, and vision interfering with work or driving, than it is on diagnostic imaging. But Dr. Baig prefers that refer- ring surgeons perform the cataract surgery and limits his use of triple procedures to cases where it is diffi- cult for the patient to travel for sur- gery and follow-up appointments. Less helpful: central corneal thickness Central corneal thickness in such patients is only useful if it is a consecutive series of measurements showing increasing thickness over time, Dr. Terry said. But there is no corneal thickness cut-off point to determine whether a surgeon should use the triple procedure or just phacoemulsification. Topography comes into play only if the corneal edema is advanced and epithelial edema prevents accurate measurement of K values for the IOL calculations needed in a triple procedure. In these types of cases, the topography from the other eye can be used if it is normal; using topical glycerin can reduce the epithelial edema; or the epithelial bullae can be scraped for the topography measurements, Dr. Terry said. Targeting spherical equivalent Kenneth Mark Goins, MD, pro- fessor of clinical ophthalmology, University of Iowa Hospitals and Clinics, Iowa City, alters the target- ed spherical equivalent in patients in which he is performing an EK through a technique that accom- modates the significant hyperopic shift that occurs after all types of EK procedures. Although combination corneal replacement and cataract surgery is becoming more predominant among some surgeons, questions still exist T he advantages of combined phacoemulsification and endothelial keratoplasty have led some surgeons to combine cataract and corneal treatments—even as they work to answer key questions for some patients. Francis W. Price, MD, Price Vision Group, Indianapolis, and chairman of the board and founder of the Cornea Research Foundation of America, Indianapolis, is among the surgeons combining procedures for most patients who need both conditions resolved. Part of the movement toward combined procedures stems from the increasing awareness about the visually disabling nature of guttae, Dr. Price said. Patients with com- bined cataracts and guttae whose chief complaint is glare and halos are probably significantly affected by the guttae, he said. "If the guttae are dense over the pupillary area, or if they are con- fluent—even if there is no edema— then I would definitely consider doing a combined procedure or just treating the guttae if the lens looks relatively clear. Even if they don't have edema, the guttae are extreme- ly disabling for these people," Dr. Price said. Part of the decision-making process is driven by patient age. Published research by the Cornea Research Foundation of America found the risk of cataract formation after Descemet's stripping endothe- lial keratoplasty (DSEK) increased sharply after age 50. "So if they are over 50, defi- nitely combine if there is a concern with the cornea," Dr. Price said. "If they are under 50 then we just do Descemet's membrane endothelial keratoplasty (DMEK) on the cornea alone." Clara Chan, MD, FRCSC, chair of the Resident Surgical Teaching Committee, Department of Oph- thalmology and Vision Sciences, University of Toronto, agreed that the comprehensive ophthalmologist should always look for guttae on clinical exam and discuss the risk for corneal decompensation and need for endothelial keratoplasty among their patients with Fuchs' dystrophy. "For most ophthalmologists without any advanced imaging devices such as endothelial specular microscopy, the simplest way to determine whether a patient with Fuchs' dystrophy can undergo cat- aract surgery alone is if the patient has no morning blurring symptoms and no clinical evidence of corneal edema—i.e., Descemet's membrane folds or stromal edema," Dr. Chan said. Slit lamp photo of diffuse guttae in Fuchs' dystrophy Source: Francis Price, MD