EyeWorld Asia-Pacific June 2017 Issue

EWAP CORNEA 53 June 2017 the corneal topography map, he said, but also the rings. If you just look at the colors, this can blend in some of the abnormalities and may not show the whole picture. Each diagnosis will be treated somewhat differently, depending on whether the physician is dealing with EBMD, Salzmann’s nodules, or another condition. There are many people with EBMD, Dr. Rapuano said. It’s a common condition, particularly as patients get older. If it’s not causing an irregularity in the tear film or on the topography, you could probably just follow it along and not treat it, he said. However, Dr. Rapuano noted that if it is causing negative staining, which can be seen on the slit lamp with fluorescein dye, then it’s probably affecting the vision and should be treated. Dr. Rapuano recommended a debridement for significant EBMD. He added that if there’s significant basement membrane left once you take the epithelium off, you can do diamond burr polishing. Phototherapeutic keratectomy (PTK) may be used in cases where there is also stromal haze or scarring, and he added that he uses mitomycin C at the time of PTK to reduce the risk of scarring. In the case of Salzmann’s nodules, those can be mild as well, he said. These can be left alone if they’re in the periphery but should be treated if they seem to be affect the visual axis. Dr. Rapuano added that distortion of rings will show up as astigmatism, and he cautioned the importance of recognizing this in the overall treatment plan. If a physician sees this and doesn’t know what’s going on in the cornea, they may treat the astigmatism, he said, and they could use a toric lens or other correction option. However, if the nodule is later treated, this would leave the patient with the initial astigmatism fix. It’s important to know whether you’re dealing with regular astigmatism or astigmatism that is secondary to something else, he said. Dr. Rapuano treats Salzmann’s nodules with excimer laser PTK with mitomycin C. Pterygium—remove or leave it? Many people have a pterygium, and Dr. Rapuano said that if it is small, peripheral, hasn’t changed, and isn’t causing a problem for the patient, then cataract surgery can be done, and the pterygium can be dealt with later. However, if the pterygium is causing a lot of astigmatism or if the physician is considering the use of a toric lens, then it may be a good idea to treat the pterygium prior to cataract surgery. If the pterygium is inducing astigmatism and the patient is interested in decreasing that astigmatism/spectacle independence, Dr. Garg prefers to stage the pterygium and cataract surgeries. “I often wait several months in between the two,” he said, until it’s possible to get stable, repeatable, and reliable measurements. Currently, Dr. Hirst’s whole practice addresses pterygium only. “Most people are wary of removing pterygia because there’s a high risk of recurrence,” he said. It’s estimated that recurrence is between 5% and 15%, he added. However, Dr. Hirst will remove pterygium more frequently and even if they are small, as he has found that his preferred removal technique has a close to zero chance for recurrence (1/2500) and a near normal appearance to the eye. “In the context of cataract and refractive surgery, I believe significant pterygia must be removed first,” he said. “And I wouldn’t undertake calculations for cataract and refractive procedures for at least 3 or 4 months after removal of the pterygium.” IOL calculations It’s important to wait an adequate amount of time after treating the corneal surface to ensure accuracy of calculations. Dr. Rapuano said that he generally waits at least 6 weeks as that is usually how long it takes to get stable, reproducible K readings, but he also noted that this can depend on the patient. Some patients may heal more slowly than that, he said. “Depending on the extent of the pathology and the desired refractive outcome, I will wait anywhere between 1 to 2 months,” Dr. Garg said. “I like to wait for the surface to improve and for reliable (and repeatable) measurements.” Helpful technologies Dr. Garg uses both topography and tomography for these patients. “It is important to determine how much irregular astigmatism is present and whether the pathology is responsible for it,” he added. “This helps make the decision on whether to proceed with removal.” Dr. Garg uses several topographers, including the OPD III (Nidek, Fremont, California) and iTrace (Tracey Technologies, Houston). He also routinely uses the Pentacam (Oculus, Arlington, Washington). Dr. Garg said he uses ORA (Alcon, Fort Worth, Texas) and noted that the accuracy really depends on how “clean” the removal is. “If there is a smooth corneal surface after removal, I find that the aberrometry is accurate,” he said. Dr. Rapuano generally uses the slit lamp and corneal topography when deciding whether to remove a corneal lump or bump. He said he does not use intraoperative aberrometry and cautioned to make sure that the IOL calculations are correct because some of these lumps or bumps may distort the aberrometry. EWAP Editors’ note: Drs. Garg, Hirst, and Rapuano have no financial interests related to their comments. Contact information Garg: gargs@uci.edu Hirst: lawrie@tapc.net.au Rapuano: cjrapuano@willseye.org