Eyeworld

70 Exploring the next generation of laser vision correction, refractive outcome goals, and practice growth strategies by Colman Kraff, MD Finding the ideal refractive target: The importance of obtaining beyond 20/20 vision Optimal visual outcomes after surgery drive patient satisfaction In addition, high quality pre- operative data are necessary, as well as customized laser systems that provide high resolution treatments. A stable ocular surface is clearly important to optimal visual out- comes. 3 I explain to refractive sur- gery patients that tear changes occur initially after LVC, and I think this is part of the natural healing process. However, tear film abnormalities may adversely affect the quality of their postoperative vision. Therefore, it is imperative to evaluate and treat the patient's tear film before surgery. Tear osmolarity can be useful in our assessment. 4 T oday's laser vision correc- tion (LVC) technologies enable surgeons to achieve visual outcomes exceeding 20/20, boosting patient sat- isfaction. Research has demonstrated that patient satisfaction correlates strongly with postoperative visual acuity and quality. 1,2 Optimization strategies Several factors contribute to out- comes beyond 20/20. Careful patient selection is key. Patients need to have normal, healthy eyes and corneas, with a normal shape and thickness. Even when patients have a normal preoperative tear layer, tear quality or tear production may change after surgery. In my expe- rience, this is magnified in certain groups, such as perimenopausal or postmenopausal women or patients taking certain systemic medications. Surgeons also need to under- stand differences in treating patients in different age groups. We usually aim to slightly overcorrect patients in their mid-20s by approximately 0.25 D. A higher percentage of these patients typically achieve postop Colman Kraff, MD by Michael Gordon, MD The next generation of laser vision correction is now: Highlighting topography-guided ablations R egardless of the technolo- gy used, the goal of laser vision correction (LVC) is to optimize patients' un- corrected visual acuity and quality of vision. Toward achieving this goal, I think topography-guided LASIK combines advantages of wave- front-optimized and wavefront-guid- ed ablations. A step further Wavefront-optimized ablation is performed using the central corneal curvature measurement, an assumed corneal shape based on a popu- lation's average Q value, and the patient's prescription. After we input this information, the laser selects a file based on those criteria to treat the patient. Topography-guided abla- tion takes this one step further. It incorporates the patient's corneal curvature, actual Q value measure- ment, prescription, and higher-order aberrations of the patient's cornea to generate a customized shot-by- shot treatment pattern. It treats aberrations of the cornea, on the cornea—not internal aberrations on the cornea. Treatment is centered over the corneal apex, not the center of the pupil. 1 the patient's prescription and corne- al keratometry. However, I think any surgeon who performs LASIK can perform this procedure. Topography-guided LASIK carries the same potential risks as traditional LASIK, such as dry eye, infection, undercorrection, over- correction, glare and halos at night, and flap complications; however, these are much less common when femtosecond lasers are used. Topography-guided ablation has not been approved for therapeutic applications in the U.S., but it has been used in Europe primarily as a therapeutic device. In a patient with progressive keratoconus, Kanellopoulos et al. re- ported improved vision and stability when topography-guided PRK was performed 1 year after UVA collagen crosslinking. 3 In 32 patients with post-LASIK corneal ectasia, Kanellopoulos et al. stated that the Athens Protocol (to- pography-guided PRK with same-day UVA collagen crosslinking) showed stability, as well as improved visual acuity in 17 of 32 eyes. 4 Reinstein et al. reported that topography-guided ablation signifi- cantly reduced stromal surface irreg- ularity and improved visual quality and topography in a patient with irregular astigmatism after LASIK. 5 Conclusion Topography-guided LASIK combines the best of wavefront-optimized and wavefront-guided LASIK in one treatment. We can achieve visual outcomes better than 20/20 in a majority of our patients, with better quality vision and less chance of glare and halos. References 1. Reinstein DZ, et al. Is topography-guided ablation profile centered on the corneal vertex better than wavefront-guided ablation profile centered on the entrance pupil? J Refract Surg. 2012;28:139–143. 2. Summary of safety and effectiveness data (SSED). Allegretto Wave Eye-Q Excimer Laser. www.accessdata.fda.gov/cdrh_docs/pdf2/ P020050S012B.pdf 3. Kanellopoulos AJ, et al. Collagen cross-link- ing (CCL) with sequential topography-guided PRK: a temporizing alternative for kerato- conus to penetrating keratoplasty. Cornea. 2007;26:891–895. 4. Kanellopoulos AJ, et al. Management of cor- neal ectasia after LASIK with combined, same- day, topography-guided partial transepithelial PRK and collagen cross-linking: the Athens Protocol. J Refract Surg. 2011;27:323–331. 5. Reinstein DZ, et al. Stromal surface topog- raphy-guided custom ablation as a repair tool for corneal irregular astigmatism. J Refract Surg. 2015;31:54–59. Dr. Gordon is a partner with Gordon Schanzlin New Vision Institute, a TLC Center located in San Diego. He can be contacted at mgordon786@gmail.com. Michael Gordon, MD Clinical data Data from the U.S. Food and Drug Administration (FDA) clinical trial for 249 eyes without previous surgery treated for myopia with or without astigmatism showed an uncorrected visual acuity (UCVA) of at least 20/12.5 in 31.6% of eyes, at least 20/16 in 68.9%, and at least 20/20 in 92.7% of eyes 3 months after topography-guided LASIK. 2 We have used topography-guid- ed LASIK for more than a year, treat- ing several hundred patients, and nearly 80% of our patients achieve UCVA of 20/15 or better, and most others are 20/20. We have performed only two enhancements. Patient selection Topography-guided ablation has been approved to treat up to 9 D of spherical equivalent, 8 D of sphere, and 3 D of myopic cylinder. We use this technology for anyone who fits within that range and for whom we can obtain good quality topography images. Topography-guided ablation is particularly useful in treating asymmetry as it relates to corneal higher-order aberrations. To optimize results from topography-guided ablations, surgeons and technicians need to obtain good, consistent topographic images. Surgeons need to develop confidence in planning treatments, which is not as simple as entering continued on page 71

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