Eyeworld

EW REFRACTIVE 72 byline goes here plus fade March 2017 This scatter "can come from anything within the optical pathway that causes light to scatter. It could be the tear film. It could be the cor- nea. It could be the backside of the cornea or the lens," and because of this, measuring it has become more important in today's clinics, Dr. Kugler said. Corneal inlays These devices are also useful with cornea-based procedures, including corneal inlays. Those devices need to be centered on the visual axis, not on the pupil. "The visual axis is a little bit harder to define because there isn't something we can point to," Dr. Kugler said. "These devices define how the light is going through the eye, and it helps us determine the relationship between the first Purkinje image, which is (basically) the reflection of the cornea," Dr. Kugler said. When the images are not aligned and surgeons implant the inlay, it can be offset by the same amount of misalignment as the devices determined. A number of devices today can show the pupil outline in relation to the corneal apex (and then where the first Purkinje reflex is) and the pupil center. The Placido disk topographers can do this as can the Scheimpflug-based devices. The combination devices that capture simultaneous whole eye wavefront maps and topographies like the iTrace (Tracey Technologies, Hous- ton), the Topcon KRW-1 (Topcon Medical Systems, Oakland, New Jer- sey) and the Nidek OPD (Gamagori, Japan) scan can also perform those functions, Dr. Cummings said. "The HD-Analyzer can addition- ally project where the Kamra inlay [AcuFocus, Irvine, California] should ideally be placed preoperatively and then confirm postoperatively where it was ultimately placed (when it's in the AcuTarget mode)," Dr. Cum- mings said. Postop corneal or refractive surgery That's not to say these devices can replace a thorough exam, Dr. Kugler said. "We still have to use clinical judgment, but these devices do give us a way to quantify the images we're capturing." For example, post-refractive or cataract surgery, some patients will be dissatisfied with their vision. These devices can help clinicians de- termine where the scatter originates. "It's also helpful in managing the patient—it can reassure them that they're not crazy, and that their scatter pattern is causing the vision issues. It means we can say 'Yes, you do have decreased vision because of the scatter, even though everybody's been telling you you're 20/20. It's not a good 20/20'," Dr. Kugler said. These devices "will help us fig- ure out why our patient is 20/20 but is still not happy," he said. "It's their biggest advantage." EW Reference 1. Lombardo M and Lombardo G. Wave aber- ration of human eyes and new descriptors of image optical quality and visual performance. J Cataract Refract Surg. 2010;36:313-31. Editor's note: The physicians have no financial interests related to their comments. Contact information: Cummings: abc@wellingtoneyeclinic.com Kugler: lkugler@kuglervision.com Devices continued from page 70 " I can show them that the chance of seeing as well as they currently do with glasses or contacts is very high because their optical system is clear. It just doesn't focus properly. " —Lance Kugler, MD

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