Eyeworld

JANUARY/FEBRUARY 2020 | SUPPLEMENT TO EYEWORLD | 5 cataract and refractive surgery patient Although we know about the Avellino group in Italy, patients who are of Korean, Japanese, or Chinese ancestry have an incidence of approx- imately 1:500 to 1:1,000 for carrying this gene. Therefore, they should be screened before refractive surgery. Patients with a family history of TGFBI dystrophy or corneal transplant for unspecified reasons also are considered high risk and should be screened before refractive surgery. In a reported case, a 25-year-old woman complained of decreasing vision 5 years af- ter LASIK in her left eye only. 1 Corneal opacities developed on the right eye, and corneal dystrophy was significantly ex- acerbated in the left eye because of her previous LASIK. This patient was confirmed geneti- cally to have GCD2. Keratoconus, ectasia screening Traditional preoperative tests to assess ectasia risk include topography, tomography, pachymetry, corneal hysteresis, and aberrometry. The hallmark of keratoco- nus is stromal thinning, but ear- ly signs include epithelial iron deposition, focal disruptions in the epithelial basement mem- brane, and breaks in Bowman's membrane. New imaging modalities may help us identify patients with ectasia. For example, Reinstein et al. studied the use of epithelial thickness profile maps for keratoconus screen- ing, and Tang et al. analyzed focal change patterns in corneal topography, pachymetry, and epithelial thickness maps to distinguish corneal warpage and keratoconus. 2,3 At the Bascom Palmer Eye Institute, clinicians are begin- ning to look at using corneal micro-layer tomography to examine the epithelial thickness, Bowman's layer, and Descem- et's membrane and to create layered maps to identify or exclude keratoconus. They are developing artificial intelligence algorithms to automate diag- nosing keratoconus and other corneal disorders. 4-6 Postoperative imaging Imaging technologies also provide valuable postoperative information. A 30-year-old LASIK patient had 20/20 vision in each eye after surgery but complained of blurring in the left eye. Ray tracing aber- rometry maps showed signifi- cant coma, which is consistent with his complaints of poor vision quality. This technology will help us with these types of patients. In a case provided by David Hardten, MD, a 78-year- old woman had cataract surgery elsewhere and had a well-cen- tered intraocular lens and YAG capsulotomy but complained of blurred vision and poor vision quality. She had mild epithelial basement membrane dystrophy and an anteriorly placed cata- ract wound with fibrosis. Dr. Hardten performed PTK and PRK with excellent Ray tracing aberrometry maps from a 30-year-old LASIK patient showing significant coma, consistent with the patient's complaints of poor quality of vision Source: Sonia H. Yoo, MD Supported by an unrestricted education grant from Avedro, Avellino Labs, Dompé, and Johnson & Johnson Vision continued on page 6

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