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document
Wavefront-guided versus standard LASIK enhancement for residual refractive errors . OBJECTIVE To assess efficacy , safety , predictability , stability , and changes in higher-order aberrations ( HOAs ) and contrast sensitivity ( CS ) after wavefront-guided and standard LASIK enhancement for the correction of residual refractive errors . DESIGN Prospective , randomized , comparative clinical study . PARTICIPANTS Twenty eyes of 20 consecutive patients ( spherical equivalent [ SE ] , -2.01+/-1.36 diopters [ D ] ) treated with wavefront-guided Zyoptix Ablation Refinement software ( ZAR ) LASIK and 20 eyes of 20 consecutive patients ( SE , -1.81+/-1.21 D ) treated with standard Planoscan LASIK , both for residual refractive error enhancement . MAIN OUTCOME MEASURES Efficacy , safety , predictability , stability , HOAs , and CS were evaluated before and after enhancement at 6 months ' follow-up . METHODS Uncorrected visual acuity ( UCVA ) , best-corrected visual acuity ( BCVA ) , manifest refraction , CS by means of the Functional Acuity Contrast Test , and HOAs by means of Zywave aberrometry were evaluated preoperatively and 6 months after retreatment . RESULTS At 6 months postoperatively , UCVA was 20/25 or better in 100 % of the eyes . Efficacy indexes were 1.09 for ZAR patients and 0.95 for Planoscan patients . No eyes lost > or =1 line of BCVA ; in the ZAR group , 2 eyes gained 1 line and 6 eyes gained > or =2 lines ; in the Planoscan group , 3 eyes gained 1 line . The ZAR group showed a percentage of eyes ( 94.4 % ) within the 0.5-D range in SE higher than that shown by the Planoscan group ( 88.8 % ) . After 6 months , the HOA root mean square ( RMS ) increased on average by a factor of 1.44 for the Planoscan group ( P = 0.003 ) . No change or reduction in HOA RMS was found in the ZAR group ( factor of 0.96 ; P > 0.01 ) . Contrast sensitivity was reduced in the Planoscan group only at the highest spatial frequency ( 18 cycles per degree ; P < 0.01 ) . There was a significant reduction of CS as a function of HOA increase for the Planoscan group ( P < 0.0001 ) . No changes were observed for the ZAR group at any spatial frequency ( 1.5-18 cycles per degree ; P > 0.01 ) . CONCLUSIONS Wavefront-guided LASIK using the ZAR algorithm is an effective and safe procedure for treatment of residual refractive errors . Wavefront-guided LASIK does not increase HOAs and does not modify CS compared with preoperative values . Wavefront-guided LASIK seems to be better than standard LASIK for retreatments .
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Intervention_Surgical
Wavefront-guided
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Intervention_Surgical
wavefront-guided Zyoptix Ablation Refinement software ( ZAR ) LASIK
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Intervention_Physical
ZAR
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Intervention_Pharmacological
Planoscan
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Intervention_Physical
ZAR
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Intervention_Physical
ZAR
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Intervention_Physical
ZAR
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Intervention_Physical
ZAR
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Intervention_Educational
Wavefront-guided LASIK
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Intervention_Educational
Wavefront-guided LASIK
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Intervention_Educational
Wavefront-guided LASIK
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Outcome_Other
efficacy , safety , predictability , stability
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Outcome_Physical
changes in higher-order aberrations ( HOAs )
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Outcome_Physical
contrast sensitivity ( CS )
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Outcome_Other
Efficacy , safety , predictability , stability
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Outcome_Physical
HOAs , and CS
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Outcome_Physical
Uncorrected visual acuity ( UCVA ) , best-corrected visual acuity ( BCVA ) , manifest refraction , CS by means of the Functional Acuity Contrast Test , and HOAs by means of Zywave aberrometry
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Outcome_Physical
UCVA
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Outcome_Other
Efficacy indexes
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Outcome_Adverse-effects
No eyes lost
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Outcome_Physical
BCVA
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Outcome_Physical
HOA root mean square ( RMS )
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Outcome_Physical
reduction in HOA RMS
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Outcome_Physical
Contrast sensitivity
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Outcome_Physical
reduction of CS as a function of HOA increase
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Outcome_Physical
spatial frequency
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Participant_Sample-size
Twenty eyes of 20 consecutive patients
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Participant_Sample-size
20 eyes
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Participant_Sample-size
20 consecutive patients
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Participant_Condition
residual refractive error enhancement