Eyeworld

6 | SUPPLEMENT TO EYEWORLD | JANUARY/FEBRUARY 2020 Brandon Ayres, MD Evolving protocols for early intervention in patients Corneal crosslinking offers new opportunities for treatment A dvanced technologies provide new opportuni- ties for early intervention in patients with keratoco- nus, with the goal of preventing end-stage complications that occur with this condition. randomized, controlled clinical trials demonstrated 1.6 D of corneal flattening in the treatment arm in patients with keratoconus compared with 1 D of steepening in the control arm. 3,4 However, changes do not occur overnight. In the first 3 months, there was 0.5 D of flattening of the cornea in patients in the treatment arm, 1 D at 6 months, and 1.6 D at 1 year. Results were similar for corneal ectasia or post-refrac- tive surgery ectasia, with ap- proximately 0.7 D of flattening at 1 year compared with 0.7 D of steepening in the control arm. In the treatment arm, there was very little flattening at 3 months, 0.5 D at 6 months, and 0.7 D by 12 months. Corneal crosslinking in practice Although we now have a 95% chance of halting progression of keratoconus, we need to prove progression to insurance companies for reimbursement. More insurance companies be- gan providing coverage during the last few years. There are a number of ways to demonstrate progres- sion, including tomography, changes in sphere or cylinder, and/or axis, keratometry, and others (Figure 1). Early intervention is critical. If we perform corneal crosslinking early, we will stop progression in most patients and reduce the need for corneal transplants. New hope In 2003, Seiler et al. published a pilot study showing that corneal crosslinking halted progression of keratoconus. 1 In a larger study, best-cor- rected visual acuity improved by 1 line or more in 53% of eyes at 1 year. 2 At 3 years, it was stable or improved in 87% of eyes. U.S. researchers began investigations, and the FDA approved an epithelium-off corneal crosslinking suite in 2016 for progressive keratoco- nus and post-refractive surgical ectasia in patients 14–65 years old. It is the only approved corneal crosslinking treatment in the United States. Clinical trials Pooled data from the two by Brandon Ayres, MD New approaches to the diagnosis and management of important corneal disorders in the cataract and refractive surgery patient results. Three months later, the patient's vision was 20/20 and she was pleased with her vision quality and uncorrected visual acuity. This example demon- strates the benefit of aberrom- etry and aberrometry-driven laser vision correction in ad- dressing quality of vision issues. A 28-year-old patient came to our office to be evaluated for refractive surgery. I had performed a bilateral cor- neal transplant on his father for keratoconus, but the son had spherical correction to 20/20 and tomography was good in both eyes. However, topographic analysis showed significant coma. After a sig- nificant amount of counseling and deliberation, we performed PRK. His uncorrected vision is 20/20 J1+ OU, but he experi- ences some nighttime glare. Conclusion New corneal diagnostic technologies help us improve our screening of preoperative refractive surgery patients and postoperative treatment. n References 1. Jun RM, et al. Avellino corneal dystrophy after LASIK. Ophthalmology. 2004;111:463–8. 2. Reinstein DZ, et al. Corneal epithelial thickness profile in the diagnosis of keratoconus. J Refract Surg. 2009;25:604–10. 3. Tang M, et al. Differentiating kera- toconus and corneal warpage by ana- lyzing focal change patterns in corneal topography, pachymetry, and epithelial thickness maps. Invest Ophthalmol Vis Sci. 2016;57:OCT544–9. 4. Vatookarn R, et al. Three-dimen- sional Bowman's microlayer optical coherence tomography for the diagno- sis of subclinical keratoconus. Invest Ophthalmol Vis Sci. 2018;59:5742. 5. Elsawy A, et al. Validation study for corneal microlayer tomography auto- matic segmentation algorithm. Invest Ophthalmol Vis Sci. 2018;59:5737. 6. Shousha MA, et al. The use of Bowman's layer vertical topograph- ic thickness map in the diagnosis of keratoconus. Ophthalmology. 2014;121:988–93. Dr. Yoo is a professor of ophthal- mology at Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami. She can be contacted at SYoo@med. miami.edu. continued from page 5 continued on page 7

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