Eyeworld Daily News

34 | EYEWORLD DAILY NEWS | MAY 18, 2020 DAILY NEWS ASCRS VIRTUAL ANNUAL MEETING complain of a loss of contrast sensitivity and glare. There are devices to quantify both. Wavefront technology can give information on all of the eye's aberrations. Light scatter can be determined with a dou- ble-pass retina point imaging device. She described other technologies and how they can help diagnose issues with qual- ity of vision in a quantifiable manner as well. She also mentioned Sim- Vis (VioBioLab) technology that can simulate the optics of different IOL choices preoper- atively and can also be helpful postoperatively in some cases. Other presentations includ- ed one on the optics of visual quality problems by Claudia Perez-Straziota, MD, Cleve- land, Ohio, and several case examples. View the full course at IC-8. Editors' note: Dr. Chang has finan- cial interests with several ophthal- mic companies. Dr. Rocha has no financial interests related to her presentation. streaks coming from the light source and can also occur with refractive error, ocular surface conditions, and PCO. These can occur in combinations as well. The size of an IOL-induced dysphotopsia has to do with add power, Dr. Chang said. Dr. Chang also posited that it might not be the amount of off-axis light causing dyspho- topsias but the pattern of the distribution. "The more you can un- derstand [what different lenses do] and describe it to the patient preoperatively, the more they tend to tolerate it and not have problems and not complain to you afterward," he said. While Dr. Chang described how and why these visu- al problems can occur with presbyopia-correcting IOLs, Karolinne Rocha, MD, PhD, Charleston, South Carolina, addressed, in part, diagnostics for these patients. Patients with higher order aberrations usually describe blurry vision, despite a good manifest refraction, while pa- tients with light scatter issues "Worst case scenario is you may offer an IOL exchange. I do IOL exchange very rarely." What causes these visu- al quality problems? Both the cornea and the IOL can contribute, Dr. Chang said. Refractive error is the most common area of vision quality problems after cataract surgery, and ocular surface disease, posterior capsule opacification, presbyopia-correcting IOL tech- nology, chromatic aberration, higher order aberrations, IOL tilt/decentration, and macular pathology can be contributing factors as well. "The good news is most of these can either be prevented or fixed," he said. Dr. Chang honed in on presbyopia-correcting IOL tech- nology and the quality of vision problems it can cause. Night vision symptoms are commonly associated with these IOLs and, in some cases, Dr. Chang said, could be preventing surgeons from offering them to patients as options. When you increase the depth of field to see closer up, the distance point of light for a distance target is out of focus because part of where the lens is focusing is not going to be on the target, so you get some off-axis light, Dr. Chang ex- plained. Dr. Chang said he uses the FDA definitions for glare/ flare, halo, and starburst. When looking at a point source of light, glare is when there is a blur around it, as seen with refractive error, ocular surface conditions, or PCO. Halo is when there is a circle around the light source and can occur with multifocal IOLs. Starbursts are when there are by Liz Hillman Editorial Co-Director P atients unhappy with their vision after cat- aract surgery require some understanding and management. An instruction course Sunday discussed how to handle these cases. The course included the following: • A description and visualiza- tions of visual quality and dysphotopsias (night vision symptoms); • Optics of visual quality prob- lems; • Diagnostic testing; and • Case presentations. This group of patients, said Daniel Chang, MD, Bakersfield, California, can be helped once you understand what's going on with their vision after cata- ract surgery. Dr. Chang started his pre- sentation with a discussion on what patients see when they come in with visual complaints, especially when they are tech- nically seeing 20/20. He discussed edge blur and described how making objects or materials bigger or bringing them closer can help reduce this symptom. Then he ad- dressed contrast and lighting. When the contrast is too dim, turn the lights up. But what about a shadow blur, which is when the image edge is crisp but there is a blur to the contrast/brightness be- hind the image. Dr. Chang said the question is whether this symptom is caused by a pres- byopia-correcting lens trying to extend the depth of field. "The good news is this kind of blur is quite uncommon," he said, adding that most patients will neuroadapt over time. Understanding and managing patients unhappy after presbyopia-correcting IOLs Dr. Chang describes different dysphotopsias and what causes them. Source: Daniel Chang, MD, screenshot from presentation

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