Eyeworld

72 | EYEWORLD | DECEMBER 2021 C ORNEA Reference 1. Goerlitz-Jessen MF, et al. Impact of epithelial basement membrane dystrophy and Salzmann nodular degeneration on biometry measurements. J Cataract Refract Surg. 2019; 45:1119–1123. Dr. Hovanesian. He also gets an OCT of the macula, which is helpful in identifying any macular disease. Since many dry eye patients are asymptom- atic, Dr. Hovanesian said a corneal topography is critical. "If we see corneal staining, that's not just dry eye, that's moderate to severe dry eye because the dryness is so advanced that it's caused a breakdown in the surface," he said. Fluorescein staining, Dr. Hovanesian said, can also help show irregularities on the cornea. Dr. Kim also discussed the importance of using fluorescein, but he warned against using too much, which can flood the tear film, making EBMD hard to spot. Dr. Kim likes to dab the palpebral conjunc- tiva with a fluorescein strip moistened with proparacaine and have the patient blink, dis- tributing a thin film that often will highlight the presence, extent, and location of EBMD. Salzmann's nodules can be missed, Dr. Kim said, because they often sit in the superior cornea. The physician needs to lift the upper lid to examine the superior cornea to spot these lesions, which can cause a lot of irregular astig- matism. Dr. Kim also stressed the importance of using corneal topography to see how much a pterygium is pulling on the cornea and causing astigmatism. The pterygium may look minor at first, he said, but the topography can help you determine the extent of central corneal in- volvement and if it needs to be treated prior to cataract surgery. "You don't need a bunch of fancy tests in your office," Dr. Kim said. Fluorescein staining, tear breakup time, and pressing on the lower lid to look for MGD are all helpful tests that can be easily performed at the slit lamp in 15–20 seconds. For pterygium, EBMD, and Salzmann's nodules, doing a good slit lamp exam, lifting the upper eyelid to make sure you visualize the entire cornea, and performing corneal topogra- phy are all important steps, Dr. Kim said. Dr. Rapuano also uses negative staining, which he said can be a valuable tool, partic- ularly for identifying basement membrane dystrophy. These alterations in the tear film indicate elevations in the corneal surface, which are often from subtle EBMD changes. While frequently mild, they can distort the vision and affect biometry, he said. Are patients already aware of these conditions? EBMD and Salzmann's nodules are usually a new diagnosis, Dr. Schallhorn said. "The patients are most commonly unaware of these conditions, as they usually don't cause symptoms, unless the patient has had previous erosions in the case of EBMD," she said. "Therefore, it is important to do a careful exam to look for evidence of these before surgery." She added that patients are usually also unaware if they have mild keratoconus. Dr. Hovanesian said patients will often attribute poor vision to the cataract rather than corneal problems. "As important as making the diagnosis is the conversation with the patient," he said. For example, if the patient has dry eye, he will explain to the patient that he or she has two diseases, not one. The first (the cataract) can be fixed, but the second (the dry eye) is up to the patient to treat, sometimes long term. "The emphasis is placed on the patient, and the conversation covers the idea that dry eye will affect vision after surgery," he said. "I can't give them perfect vision because their eye is not per- fect even with the cataract removed." Tests to perform Corneal topography has become an important part of preoperative evaluation of patients for Visually significant central EBMD changes are highlighted by negative staining using fluorescein dye and the cobalt blue light. Source: Christopher Rapuano, MD continued from page 71

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