Eyeworld

EW NEWS & OPINION June 2017 23 CDVA to preoperative CDVA. The mean safety was 0.96 ± 0.12 D after LASIK and increased to 0.99 ± 0.15 D after retreatment (P=.004). Dr. Frings observed stable and high safety after LASIK and retreatment, with no in- fluence of preoperative manifest SE, manifest cylinder or KM. Using linear regression to analyze predictability revealed that 92 eyes (81%) were beyond ±0.50 D of the attempted correction after LASIK. Of the 92 eyes outside this interval, 73 (79.3%) were undercor- rected by 1.00 D or more in terms of attempted SE change, and this was more common and statistically significant in eyes with a preopera- tive SE of more than 2.50 D (P=.005, tested with chi-square test). While still showing a trend toward under- correction, retreatment resulted in 88 eyes (78%) that reached ±0.50 D of the attempted correction. "Retreatment after hyperopic LASIK in eyes with a preoperative difference between cycloplegic and manifest refraction of 1.00 D or less results in higher efficacy, predict- ability, and safety when the surgery is based on manifest refraction," Dr. Frings said. "The efficacy and safety of the retreatments are not influenced by preoperative manifest SE, manifest cylinder, KM, or OZ diameter, whereas the treatment pre- dictability was significantly lower in eyes with a preoperative SE of 2.50 D or more. Further studies are warrant- ed to investigate the role of cyclople- gic refraction in LASIK treatment for hyperopia." EW References 1. Mimouni M, et al. Factors predicting the need for retreatment after laser refractive surgery. Cornea. 2016;35:607–12. 2. Dupps WJ, et al. Standardized graphs and terms for refractive surgery results. J Cataract Refract Surg. 2011;37:1–3. Editors' note: Dr. Frings has no finan- cial interests related to his comments. Contact information Frings: andreas.frings@med.uni-duesseldorf.de satisfied with their distance correct- ed visual acuity (DCVA) and eyes deviating by 0.50 D of spherical equivalent (SE) or more from target but with stable manifest and cyclo- plegic refraction. The retrospective study iden- tified 113 eyes of 113 consecutive hyperopic patients of which 52 (46%) were male and 61 (54%) were female (P=.138) who had a mean age of 47 years (range, 21 to 63 years). Dr. Frings analyzed their refractive outcomes according to standard graphs for reporting the efficacy, predictability, and safety of refrac- tive surgery 2 as well as the influence of preoperative manifest spherical equivalent (SE, ≤2.50 D versus >2.50 D), manifest cylinder (≤1.00 D versus >1.00 D), and keratometry (KM; ≤44.00 D versus >44.00 D) on efficacy and safety. For the statistical analysis, he applied either the paired samples T-test or Wilcoxon matched-pairs signed-rank test depending on the distribution of the differences before and after LASIK. In his analysis of the changes in biometrical data from before and after the first LASIK, the mean manifest SE was 2.78 ± 0.86 D preoperatively, and 1.03 ± 0.60 D postoperatively (P<.001). The mean manifest SE after retreatment was 0.27 ± 0.47 D (P<.001). A P value of 0.05 or less was defined as statistical- ly significant. Efficacy The efficacy index was calculated using the mean of the ratio of post- operative UDVA to the preoperative CDVA. The mean efficacy was 0.68 ± 0.21 D for LASIK and increased to 0.93 ± 0.18 D after retreatment (P<.001). There was a shift to higher efficacy after retreatment with a postoperative UDVA equivalent to the preoperative CDVA in 85 (75%) of the study eyes. Furthermore, there was no influence of the preoperative manifest SE (≤2.50 D versus >2.50 D), manifest cylinder (≤1.00 D ver- sus >1.00 D), or KM (≤44.00 D versus >44.00 D) on efficacy and safety of retreatment. Safety and predictability The safety index was represented by the mean ratio of postoperative

• Blank Page
• Blank Page (1)