Comparative analysis of the efficacy of astigmatic correction after wavefront-guided and wavefront-optimized LASIK in low and moderate myopic eyes

AIM： To evaluate and compare the efficacy of the astigmatic correction achieved with laser in situ keratomileusis（LASIK） in eyes with myopic astigmatism using wavefront-guided（WFG） and wavefront-optimized（WFO） ablation profiles.METHODS： Prospective study included 221 eyes undergoing LASIK： 99 and 122 eyes with low and moderate myopic astigmatism（low and moderate myopia groups）.Two subgroups were differentiated in each group according to the ablation profile： WFG subgroup,109 eyes（45/64,low/moderate myopia groups） treated using the Advanced Custom Vue platform（Abbott Medical Optics Inc.）,and WFO subgroup,112 eyes（54/58,low/moderate myopia groups） treated using the EX-500 platform（Alcon）.Clinical outcomes were evaluated during a 6-month follow-up,including a vector analysis of astigmatic changes.RESULTS： Significantly better postoperative uncorrected visual acuity and efficacy index was found in the WFG subgroups of each group（P≤0.041）.Postoperative spherical equivalent and cylinder were significantly higher in WFO subgroups（P≤0.003）.In moderate myopia group,a higher percentage of eyes with a postoperative cylinder ≤0.25 D was found in the WFG subgroup（90.6% vs 65.5%,P=0.002）.In low and moderate myopia groups,the difference vector was significantly higher in the WFO subgroup compared to WFG（P〈0.001）.In moderate myopia group,the magnitude（P=0.008） and angle of error（P〈0.001） were also significantly higher in the WFO subgroup.Significantlyless induction of high order aberrations were found with WFG treatments in both low and moderate myopia groups（P≤0.006）.CONCLUSION： A more efficacious correction of myopic astigmatism providing a better visual outcome is achieved with WFG LASIK compared to WFO LASIK.

Wavefront-optimized surface retreatments of refractive error following previous laser refractive surgery: a retrospective study

Background:Retreatments are sometimes necessary to correct residual or induced refractive errors following refractive surgery.Many different combinations of primary treatment methods and retreatment techniques have been studied,however,few studies have investigated wavefront-optimized(WFO)technology for retreatment following primary refractive surgery.This study aimed to report the outcomes of WFO photorefractive keratectomy(PRK)retreatments of refractive error following previous laser refractive surgery with PRK,laser in situ keratomileusis(LASIK),or laser-assisted subepithelial keratectomy(LASEK).Methods:We reviewed records of patients who underwent WFO PRK retreatments using the Allegretto Wave Eye-Q 400 Hz Excimer Laser System(Alcon Surgical)between January 2008 and April 2011 at Walter Reed Army Medical Center and Madigan Army Medical Center.Outcomes were recorded in terms of uncorrected distance visual acuity(UDVA),manifest refraction spherical equivalent(MRSE),corrected distance visual acuity(CDVA),and complications at 1 month(M),3 M,and 6 M post-op.Results:Seventy-eight patients(120 eyes)underwent WFO PRK retreatment during the study period.Primary surgery was surface ablation in 87 eyes(78 PRK,9 LASEK)and LASIK in 33 eyes.The mean spherical equivalent before retreatment was−0.79±0.94 D(−3.00 to 1.88 D).UDVA was≥20/20 in 69 eyes(60.0%)at 1 M,54 eyes(71.1%)at 3 M,and 27 eyes(73.0%)at 6 M follow-up.MRSE was within±0.50 D of emmetropia in 78 eyes(67.8%)at 1 M,59 eyes(77.6%)at 3 M,and 25 eyes(67.6%)at 6 M follow-up.CDVA was maintained within±1 line of pre-op in 113 of 115 eyes(98.3%)at 1 M,74 of 76 eyes(97.4%)at 3 M,and 37 eyes(100%)at 6 M follow-up.Conclusion:Although follow-up was limited beyond 3 M,WFO PRK retreatments in patients with residual refractive error may be a safe and effective procedure.Further studies are necessary to determine the long-term safety and stability of outcomes.