EyeWorld Asia-Pacific March 2018 Issue

by Maxine Lipner EyeWorld Senior Contributing Writer Complexities of negative dysphotopsia Examining the effect of IOL orientation in negative dysphotopsia cases O ne complication that can occur after routine cata- ract surgery is dysphotop- sia. This is prevalent and can be bothersome, according to Bonnie Henderson, MD , clinical professor of ophthalmology, Tufts University School of Medicine, Boston. “While positive dysphotop- sia may be more common, negative dysphotopsia represents a bigger challenge when it persists,” Dr. Henderson said. “It affects up to 15.2% of patients immediately fol- lowing surgery and can gradually resolve. However, in up to 2–3% of patients, the symptoms remain.” In a study published in the Asia-Pacific Journal of Ophthalmol- ogy , 1 investigators took a closer look at the effect of the orientation of the IOL in such cases. Shadowy existence Cases of negative dysphotopsia may not necessarily be dramatic, however, they can annoy patients. “Negative dysphotopsia is described as a dark shadow in the periphery,” Dr. Henderson said. Symptoms usu- ally disappear if the eye is shielded on the temporal side from the light originating there. Dr. Henderson first began looking into negative dysphotopsia after a referred patient came to her with some unusual complaints. “Her vision was good but she was bothered by a persistent temporal shadow,” Dr. Henderson said. “She stated that when she cupped her hand to the side of her eye or when she looked downward, the shadow disappeared.” After considering this observation, Dr. Henderson hypothesized that by blocking the light she could be eliminating the shadow. To support this theory, she started to read the peer-reviewed literature on the subject. “Based on the work of Jack Holladay, MD , I started to understand that the light could be striking the edge of the IOL and causing a gap in the illuminated retina,” she said. Dr. Henderson reasoned that this might allow for a remedy. “If the amount of light striking the edge of the IOL could be minimized, then possibly the incidence of negative dysphotopsia could be decreased by adjusting the orientation of the IOL,” she said. “Since there is no edge of the optic in the optic/haptic junction, we wondered if position- ing the junction in the nasal/tem- poral orientation would decrease the amount of edge that would be available to cause the dark shadow.” With this in mind, investiga- tors launched the prospective study. Included were those who were undergoing cataract surgery in both eyes. Patients were not told the orientation of their IOLs, Dr. Henderson stressed. “In one eye, the IOL was placed in the study position (inferotemporally/supero- nasally), and in the other eye, the IOL was placed in the control posi- tion (12 and 6 o’clock),” she said. All the IOLs used here were one- piece acrylic IOLs. Another group of eyes had implantation of silicone three-piece IOLs in different orien- tations. The patients were brought back for follow-up at 1 day, 1 week, and 3–4 weeks postoperatively and evaluated for symptoms of negative dysphotopsia, and the orientation of the IOL was noted. Investigators saw a connection. “We found a 2.3-fold decrease in the incidence of negative dyspho- topsia when the optic junctions of the acrylic one-piece IOL were placed in the horizontal infer- otemporal/ superonasal position,” Dr. Henderson said. “The finding supported our hypothesis that orienting the IOL to minimize the amount of exposed optic edge de- creased the patient-reported symp- toms of negative dysphotopsia.” This significant decrease, however, was only seen in the immedi- ate postoperative period. By the 1-month mark, symptoms of the condition had decreased in both IOL groups, and there was no longer a significant difference found in the incidence of negative dysphotopsia between the control and the study group, Dr. Henderson noted. More research still needed Practitioners are potentially in a position to prevent this from occur- ring in many cases. Dr. Henderson advises those who are using a one- piece acrylic IOL to orient the lens with the optic/haptic junction in the horizontal temporal/nasal posi- tion instead of the vertical superior/ inferior position to help keep nega- tive dysphotopsia at bay. If a case of negative dyspho- topsia does occur, there are many approaches to treat this, including exchanging the IOL, piggybacking a sulcus lens in the eye, using laser anterior capsulotomy and prolaps- ing the optic for a reverse optic capture. “Unfortunately, none of the treatments are foolproof,” Dr. Henderson said. “There are reports of success with each of these treat- ments, but there have also been reports of failures with each.” Dr. Henderson stressed that the cause of negative dysphotopsia is multifactorial. “As we continue to learn more about this phenomenon, we will hopefully be able to find ap- propriate methods to avoid or elimi- nate it,” she said. “The ophthalmic community has to work together to find solutions.” EWAP Reference 1. Geneva I, et al. The complexities of negative dysphotopsia. Asia Pac J Ophthalmol (Phila). 2017;6:364–371. Editors’ note: Dr. Henderson has no financial interests related to her com- ments. Contact information Henderson: bahenderson@eyeboston. com Negative dysphotopsia, seen here, can be an annoyance to patients. Source: Bonnie Henderson, MD EWAP CATARACT/IOL March 2018 27