EyeWorld Asia-Pacific June 2014 Issue

31 EWAP CAtArACt/IOL Pseudophakic dysphotopsia June 2014 Myoung Joon KIM, MD, PhD Associate Professor, University of Ulsan College of Medicine, Asan Medical Center Dept. of Ophthalmology, Asan Medical Center, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, Republic of Korea Tel. no. +82-2-3010-3975 (office) Fax no. +82-2-470-6440 mjmjkim@gmail.com P seudophakic dysphotopsia following uneventful cataract surgery is more common than we think, and the rate of such complaints may be increasing as patients’ expectations also increase. Patients often say “It looks something like a flash, flies or threads.” As a matter of fact, vitreous floaters as well as pseudophakic dysphotopsia can present with similar symptoms and sometimes it is very difficult to distinguish the symptoms caused by vitreous floaters from those of pseudophakic dysphotopsia. There are two kinds of dysphotopsia. First, positive dysphotopsia is the presence of unwanted images like a flash and an arc, which may be associated with light scattering by square-edge IOLs and acrylic material. Conversely, negative dysphotopsia is the presence of unwanted images such as a shadow, which may be associated with square-edge optics, contracted anterior capsule, relative location of the functional retina, or a combination of these factors. It appears that although pseudophakic dysphotopsia after monofocal IOL implantation may persist, it can decrease to a tolerable level with time. I usually think that if the patients receive a proper explanation and reassurance, it will often not be a problem. I personally have never performed any surgical approach for patients with dysphotopsia, and think that the “wait and see” method is the first approach for monofocal pseudophakic dysphotopsia. On the other hand, dysphotopsia following multifocal IOL implantation will often be problematic. Venter JA et al.1 reported that 55 of 9,366 eyes with zonal refractive multifocal IOL experienced severe dysphotopsia requiring IOL exchange. In our hospital, we have experienced cases of IOL exchange because of dysphotopsia after multifocal IOL implantations which include zonal refractive multifocal IOLs and diffractive multifocal IOLs. Therefore, I think that in cases of dysphotopsia after multifocal IOL implantation, it is important to meticulously evaluate the patient`s symptoms, as various causes are possible. I would emphasize evaluation of the ocular surface not only preoperatively but also postoperatively. For the treatment, approaches from low-hanging fruit are recommended. Treatments include ocular surface management, YAG capsulotomy, IOL repositioning, Piggybacking if IOLs and so on; the last option would be IOL exchange. It is true that dysphotopsia is drawing more and more attention from cataract surgeons. Collection, registration, and analysis of dysphotopsia cases will be needed for better understanding of the etiology, detailed classification, and treatment guidelines. Reference 1. Venter JA, Pelouskova M, Collins BM, Schallhorn SC, Hannan SJ. Visual outcomes and patient satisfaction in 9366 eyes using a refractive segmented multifocal intraocular lens. J Cataract Refract Surg. Oct 2013;39(10):1477-1484. Editors’ note: Dr. Kim has no financial interests related to his comments. YAO Ke, MD Professor, Eye Institute of Zhejiang University Eye Center, Second Affiliated Hospital of Zhejiang University, College of Medicine 88 Jiefang Road, Hangzhou, 310009, China Tel./Fax no. +86-571-87783897 xlren@zju.edu.cn T he articles “Understanding positive dysphotopsia” by Michelle Dalton and “Treating, eliminating negative dysphotopsia” by Vanessa Caceres reveal the characteristics of negative and positive dysphotopsia and also possible causes and treatments. “Managing multifocal IOL dysphotopsia” by Ellen Stodola focused on the management of dysphotopsia with multifocal IOL. Since it was first reported in 2000 by James Davison, “dysphotopsia” has become a hot topic in the field of cataract surgery. Postoperatively, we usually concentrate on visual acuity, but later we find some patients with “unhappy 20/20”. Though the surgery was considered to be perfect, the patients had many complaints. The visual symptoms complained of by patients can be shadows, arcs, flashes, halos, even constriction of visual fields. It was even more severe and common after multifocal intraocular lens implantation. Some of the symptoms can resolve by themselves with time but very few can’t. It really upsets the patients and surgeons. Luckily, we get to know the nature of the problem, although the exact mechanism of the phenomenon is still under controversy. In my experience, the incidence of dysphotopsia appears to be 1% to 2% in my patients and it rises to 3% to 5% in patients who receive multifocal IOLs. As the phenomenon has not been totally explained, we try some steps to prevent it. First, selection standards are very important before surgery. We will have a comprehensive evaluation of the patients depending on his/her ocular condition, visual habits, occupation, and personalities. For these night drivers, large pupil or sensitive patients, we will not recommend multifocal IOLs. For patients with irregular topography, we would prefer zero aspheric IOLs. During the surgery, a well-bag-centered IOL implantation can help to reduce the risk of dysphotopsia. We would like to overlap the capsulorhexis rim over the edge of IOL and the peripheral capsular opacification will decrease the symptoms. Once dysphotopsia occurs in postoperative patients, follow-up is the first choice. Most dysphotopsias will be eliminated after 3 to 6 months of neuroadaptation and don’t need intervention. If it continues, spectacles or YAG laser capsulectomy may help. For patients with persistent symptoms, an IOL exchange would be an alternative choice. With the application of femtosecond laser in phacoemulsification, the accuracy and prediction of capsulorhexis is much better than conventional phacoemulsification. We hope it would diminish dysphotopsia and it still needs further evaluation. Editors’ note: Dr. Yao has no financial interests related to his comments. Views from Asia-Pacific