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R efractive surgeons avoid LASIK in certain popula- tions because of a concern over dry eye and to avoid the potential for ectasia that LASIK brings, and about 18% of ASCRS members currently perform PRK instead. Yet we know LASIK has an incredibly high patient satisfac- tion rate and much faster visual recovery than PRK, so the question remains: Are we being overly cautious by performing surface ablative techniques? One of the largest cohorts to date (more than 45,000 eyes) would seem to suggest we are. Optical Express conducted a visual recovery analysis of 1,846 eyes that underwent PRK compared to 44,475 eyes that underwent LASIK in 2013; fairly standard inclusion criteria were used, including that evaluations were on eyes that had primary laser vision correction procedures only, procedures had to be consecutive, and ablation profiles used CustomVue with the VISX Star S-4 (wavefront-guided) (Abbott Medical Optics, AMO, Santa Ana, Calif.). For LASIK, the femtosecond flaps were all created with the IntraLase laser (AMO). Follow-up was at 1 day, 1 week, 1 month, and 3 months. At baseline, the mean preop best corrected visual acuities (BCVA) were identical: –0.09±0.05 logMAR. There were statistically significant differ- ences in the two groups in mean myopia (–2.97±1.90 D in the LASIK group, –2.85±1.93 D in the PRK group; P=0.0099) and in mean hyperopia (+1.83±0.98 D in the LASIK group and +1.57±0.95 in the PRK group; P=0.0003). There were more myopes in the PRK group (89%) than in the LASIK group (85%). There were 43% of patients in the PRK group with –1 D to –2 D manifest preop sphere, and 40% in the LASIK group. Manifest preop cylinder was fairly well matched, too, with 53% in the PRK group and 51% in the LASIK group at –1 D. Early postop data favors LASIK The postoperative uncorrected distance visual acuity (UCDVA) significantly favored LASIK in percentage of patients reaching 20/16 by all time points up to 1 month. At day 1, 72% of LASIK patients but only 9% of PRK patients reached 20/16. Binocular UCDVA outcomes for LASIK vs. PRK patients reaching 20/20 were: 90% vs. 23% at day 1, 93% vs. 61% at week 1, and 95% vs. 84% at month 1, respectively. Correlating preop data to ectasia risk With data from more than 205,000 patients treated with LASIK or LASEK between 2007 and 2011, an Optical Express analysis found the overall ectasia rate is rather small— 0.028% (n=58). Of potential interest, however, is that the anterior curva- ture appeared to be most predictive, while posterior elevation was a lower predictive value. Using the Randleman Ectasia Risk Score System 1 to categorize eyes, 16,375 were considered "high" risk. Of those, only eight eyes developed ectasia, leading to the conclusion that the Randleman Ectasia Risk Score System on its own has a low predictive value. Some patients, therefore, may have been excluded from LASIK for reasons that seem to have little statistical justification. It is also worth men- tioning that the natural incidence of keratoconus should lead to the development of some new cases of ectasia in a population of more than 16,000 carefully monitored eyes, even without surgical intervention. Patients prefer LASIK More importantly, patients are sub- jectively reporting better outcomes with LASIK earlier than with PRK. Not only does that contribute to the "wow" factor, but may impact referrals. Patients preferred LASIK (93% were "satisfied") to PRK (84%) at month 1 (P<0.0001); by month 3 the differences were not statistically significant, although patients did continue to prefer LASIK more. The majority of patients in both groups reported "none/a little" dry eye discomfort at month 1, but again, patients in the LASIK group had better outcomes (85%) com- pared to PRK (79%; P=0.0015). By month 3, the differences were not statistically significant, but still favored LASIK over PRK (90% vs. 87%, respectively). At month 1, starburst or halos only affected 10% of patients in either group, and by month 3, only affected 6% of LASIK patients and 5% of PRK patients. Practice economics Determining which procedure is better for the health of the practice is multifactorial. The inherent delay in short-term visual recovery in PRK patients leads to fewer patient-to- patient referrals—up to 2 per procedure, according to a survey of leading surgeons. PRK patients need close to an additional 20 hours of follow-up, whereas the LASIK patient is often seen only once or twice after the initial surgery. 2 That additional chair time with the PRK patient is lost revenue and far out- weighs the cost of femtosecond up- grades for LASIK. The longer visual by Steven J. Dell, MD Re-examining visual recovery in the LVC patient "Some patients, therefore, may have been excluded from LASIK for reasons that seem to have little statistical justification." Steven J. Dell, MD 11 Figure 1. Percentage of patients reaching 20/16 by time point Data courtesy of Optical Express continued on page 13 Corneal refractive surgery

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