Eyeworld

68 | EYEWORLD | APRIL 2023 R EFRACTIVE Contact Schallhorn: jschallhorn@gmail.com Waring: georgewaringiv@gmail.com Reference 1. Gouvea L, et al. Objective as- sessment of optical quality in dry eye disease using a double-pass imaging system. Clin Ophthal- mol. 2019;13:1991–1996. Relevant disclosures Schallhorn: Carl Zeiss Meditec, Novus Vision Waring: Johnson & Johnson Vision, Oculus, Tracey Technologies, Visiometrics will receive an automated tear breakup mea- surement with the Oculus Keratograph and an anterior segment OCT device to image the epi- thelium, Dr. Schallhorn said. "This can help de- termine the source of the irregularities seen on Placido disc imaging or exam," she explained. Dr. Schallhorn said maintaining a stable tear film is key to achieving the best possible image quality. "For the vast majority of patients, this is the major modifiable factor in image quality. Paying attention to tear film stability and managing lid health is of utmost impor- tance. Many patients can have an unstable tear film but not report dry eye symptoms, so paying attention to the exam findings is the only way to detect this." Dr. Waring said he considers all of these technologies that have enabled and improved assessment of image quality important to the staged approach of assessing current image quality and image quality potential from the front to back of the eye. "What may have been thought of as nice to have 10 years ago can be a need to have 10 years later," he said. "It depends on the prac- tice pattern of the surgeon and the goals of the surgeon and the patient." Dr. Schallhorn said her most vital measure- ments for cataract surgery are a thorough exam and Placido disc topography. "This will tell you most of what you need to know," she said. The other important contributor to image quality is the retina. Routine preoperative macular OCT should be performed in any patient considering an advanced-technology IOL, as even subtle findings can affect the outcome of surgery. In patients with abnormal topography, com- bined ray tracing/Placido disc imaging is nice to have to sort out the relative contribution of the cornea and lens to image quality, Dr. Schallhorn said, noting that this technology is essential for the 45- to 60-year-old age group deciding between lens vs. corneal surgery. For patients with irregular topography and early cataracts, knowing the relative contribution of each to the image quality can be helpful in preoperative patient counseling and setting expectations. "As the diagnostic capabilities of our imag- ing devices continue to advance, we can start to move the conversation and the goal of surgery beyond a simple acuity number and into an era of optimizing image quality," she said. If we identify EBMD, more times than not we recommend a staged procedure with a super- ficial keratectomy first … letting the cornea resurface, which often regularizes the previous irregular astigmatism," Dr. Waring said. Dr. Waring further explained the role of the vitreous on optical dysfunction, crediting the work of Jerry Sebag, MD, on this front. He said that more attention is being paid to this objectively and subjectively so patients can be counseled appropriately. For example, if the patient had vitreous opacities preoperatively but didn't know about them, they might blame the procedure on poor visual quality when it was an existing condition. Advanced preoperative image quality diagnostics, Dr. Waring continued, can help the surgeon determine where the patient falls in their stage of ocular maturity. We may have a 50-year-old with complaints of glare referred for cataract, Dr. Waring said, but with advanced diagnostics, the source of the glare could be found to be keratoconus, not to be confused with a patient who may only be at the first stage of dysfunctional lens syndrome. "Not only do we get a better understand- ing of their image quality preop, but we gain a better understanding of their source of optical dysfunction to make better decisions about their care and to educate them better." Julie Schallhorn, MD, said in an email to EyeWorld that her preop IQ testing includes a combination of standard exam maneuvers, paying particular attention to the ocular surface and eyelids, as well as imaging of the shape of the cornea and of the tear film. "Every preop cataract patient gets a full exam and Placido disc topography and Scheimp- flug tomography, and every preop refractive sur- gery patient also gets an anterior segment OCT with epithelial thickness mapping," she said. "Refractive patients with any evidence of lens changes on exam or those older than 45 also undergo combined Placido disc/ray tracing im- aging (iTrace) to determine the relative impact of lenticular changes on visual quality. In cata- ract patients with irregular corneas, I will also obtain an iTrace to help determine the relative contribution of the corneal shape abnormalities vs. the lens opacity to visual quality." If she finds these measurements/images are normal, that's the entirety of her preop workup. Cataract patients who have an unstable tear film continued from page 66

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