EyeWorld Asia-Pacific December 2019 Issue

30 EWAP DECEMBER 2019 SECONDARY FEATURE O ne early morning at the 32nd APACRS annual meeting held in Kyoto from 3 to 5 October 2019, ÌÜ iÝ«iÀÌÃ ÜiÀi ÛÌi` Ì deliver special interest lectures in a “Rising Sun” symposium. Terry Kim, MD, discussed “Cataract surgery on the atypical cornea” and Michael Lawless, MD, endeavored to answer the deceptively simple question “How to determine when a V>Ì>À>VÌ Ã ÛÃÕ>Þ Ã}wV>Ì¶» The atypical cornea Patients with atypical corneas may be asymptomatic, but any abnormality in the cornea can affect preop measurements. Since refractive outcomes rely on accurate readings and measurements, this translates to > ivviVÌ w> ÛÃÕ> ÕÌVi° It is now generally accepted that contact lens wear affects keratometry readings, but according to Dr. Kim there has been very little published on the topic. Dr. Kim and his colleagues published a paper looking at a retrospective interventional case series of patients with a history of contact lens use who presented for cataract surgery. 1 In a small study population of 26 eyes with a mean duration of contact lens use of 35 years (ranging from 14 to 35 years), patients were asked to go on a hiatus from using the contact lens an average of 18 days (9–30 days) prior to surgery. Taking measurements pre- and post-hiatus, Dr. Kim and his colleagues saw less variable >ÝÃ i>ÃÕÀiiÌÃ {°£Â «Ài >ÌÕÃ ÛÃ° £°ÓÂ «ÃÌ>ÌÕÃ] p<0.01) and a mean change >ÝÃ v È°ÎÂ° º/Ã Ü>Ã £x iÞiÃ >vÌiÀ iÝVÕÃ v iÞiÃ with <1.0 D astigmatism due to more inherent variability when measuring low astigmatism,” Dr. Kim said. Moreover, IOL power selection changed in 12 out of 26 eyes—9 IOLs changed by 0.5 D, 3 IOLs changed by 1.0 D. Using >1.0 D astigmatism as cutoff for toric IOL candidacy, 3 iÞiÃ ÜiÀi µÕ>wi` >` £ iÞi `ÃµÕ>wi` >vÌiÀ>ÌÕÃ° " toricity changed for 7 out of 11 eyes; 6 eyes changed by 0.75 D of IOL cylinder, 1 eye by 1.50 D of IOL cylinder. “Based on our small study, we think that contact lens wear may affect biometry measurements and subsequent IOL power and toricity selection,” Dr. Kim said. “For some eyes, repeating biometry measurements following a contact lens hiatus may improve the accuracy of IOL calculations.” He further noted that patients wearing contact lenses frequently have concomitant dry eyes, and he recommended a hiatus of about 2 weeks for soft contact lens use, 3 weeks for soft toric contact lens use, and 3 weeks per decade of wear for RGP contact lens use. Dr. Kim also looked at other corneal conditions that can affect cataract surgery patients. Epithelial basement membrane dystrophy (EBMD) is one such condition—one that is frequently overlooked, unrecognized, underdiagnosed, and untreated. On topography, these corneas have a very irregular pattern of astigmatism. In these cases, i ÀiVi`i` ÃÕ«iÀwV> keratotomy. Describing his technique vÀ ÃÕ«iÀwV> iÀ>ÌÌÞ these cases, he said that he usually marks the epithlium, uses 20% ethanol for 20–30 seconds which he then wipes ÜÌ> 7iÝi Ã«}i Ì âi trauma to the endothelial cells, >` w>Þ Ì>iÃ > Ã«>ÌÕ> Ì remove the duplicated basement membrane. All this, he said, can Li `i Õ`iÀ > iÝViÀ >ÃiÀ microscope. Surgeons can also use a diamond burr to smooth the surface out, and place a bandage contact lens until it heals. Finally, Dr. Kim discussed the impact of Salzmann’s nodular degeneration—particularly cases with nodules at the 10 and 2 o’clock positions. He recommends taking these cases to the minor OR and, using 0.2 forceps, aim for the edge of the lesion, identify the plane of the Bowman’s layer, and peel off the nodules—which, he said, “respect the Bowman’s layer.” À° VVÕ`i`\ º9Õ should really be aware of these conditions, look for them, and, once you diagnose, treat them in order to optimize your biometry measurements.” Determining when a cataract is visually UKIPKƂECPV According to Dr. Lawless, the process for deciding when to perform cataract surgery has recently tended to be taken away from surgeons by Rising Sun Special interest lectures by Chiles Aedam R. Samaniego Þi7À` čÃ>*>VwV -iÀ -Ì>vv 7ÀÌiÀ