EyeWorld Asia-Pacific June 2014 Issue

33 EWAP CAtArACt/IOL Pseudophakic dysphotopsia June 2014 Treating, eliminating negative dysphotopsia by Vanessa Caceres EyeWorld Contributing Writer Treatments linked to suspected causes; prevention remains under investigation T he best way to treat negative dysphotopsia remains a hot topic among surgeons. Negative dysphotopsia that occurs right after cataract surgery is usually best left to resolve on its own. However, if the problem continues a few months after surgery, ophthalmologists must step in to provide a treatment. Their treatment approach usually depends on what they suspect is the cause. Looking at causes Negative dysphotopsia appears in patients as a temporal crescentshaped shadow after in-the-bag IOL implantation following cataract surgery. It was first reported in 2000 by James Davison, MD , cataract and refractive specialist, Wolfe Eye Clinic, with locations throughout Iowa. 1 Dr. Davison said he observed the phenomenon with acrylic square-edge IOLs, which were introduced in the 1990s as a way to prevent posterior capsule opacification. “There’s controversy with the exact mechanism of action,” said David V. Folden, MD , North Suburban Eye Specialists, Minneapolis, Minn., U.S. “I think more physicians and data would support the fact that it’s ultimately the sharp posterior optic edge design of the modern-day IOL that’s likely the culprit.” Other suggested factors include an IOL’s high index of refraction, transparency of the peripheral nasal capsule, and type of incision used during surgery. The immediate postop incidence for negative dysphotopsia appears to be around 20%, said Samuel Masket, MD , in private practice in Los Angeles, Calif., U.S., and clinical professor of ophthalmology, Jules Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, Calif., U.S. However, long-term chronic dysphotopsia complaints are closer to 1.5% to 3%, Dr. Masket said. Surgeons cannot yet predict who will experience negative dysphotopsia, said Jack T. Holladay, MD , clinical professor of ophthalmology, Baylor College of Medicine, Houston, Texas, U.S. Dr. Holladay wrote an article in 2011 that used ray tracing diagrams to explain negative dysphotopsia. 2 “The peripheral arcuate shadow that patients see is the result of square-edge optics causing a refraction of the rays that pass through the edge of the lens that go in opposite directions (leaving a blind spot), and that creates a shadow,” he said. “That always happens. If that shadow falls anterior to the functional retina, then you can’t see it. If it falls on the functional retina then you’ll see it.” “Not everyone’s peripheral retina is at the same point. People who have a functional retina extending far anteriorly will have a higher chance of experiencing this than people who don’t,” Dr. Holladay said. “We have no clinical way of determining how far a patient’s functional retina goes.” However, Dr. Holladay added that if someone experiences negative dysphotopsia in one eye, it’s more likely that he or she will experience it in the fellow eye as well. Slit lamp image shows the nasal anterior capsule overlying the anterior surface of the IOL optic prior to Nd:YAG laser anterior capsulectomy. The creation of an anterior capsule sector along the nasal aspect of the capsulorhexis following Nd:YAG laser anterior capsulectomy. Source (all): David Folden, MD; J Cataract Refract Surg. 2013;39:1110-1115 continued on page 36