title: Measurement of contrast sensitivity and glare under mesopic and photopic conditions following wavefront-guided and conventional LASIK surgery.
abstract: OBJECTIVE
  To compare contrast and glare vision in a prospective study of eyes treated using conventional and wavefront-guided LASIK surgery. The reproducibility of a glaremeter device used to quantitatively measure glare and halo was also determined.
  
  
  METHODS
  Ninety-two eyes of 46 patients underwent conventional LASIK surgery and 104 eyes of 52 patients underwent wavefront-guided LASIK surgery. Visual acuity, glare disability measured using a glaremeter, and contrast sensitivity assessed using a Pelli-Robson chart were measured monthly for 6 months postoperatively. Glaremeter testing was performed under both mesopic (5.4 +/- 0.4 cd/m2) and photopic (78.3 +/- 4.4 cd/m2) conditions. To evaluate the reproducibility of the glaremeter, 36 eyes of 18 nonoperated myopic patients were tested.
  
  
  RESULTS
  The coefficient of variation and the reliability coefficient for the glare test were 13.6% and 95.2%, respectively. The glaremeter showed that glare disability under mesopic conditions differed between conventional and wavefront-guided LASIK eyes over 6-month follow-up (907.5 +/- 491.5 vs 986.1 +/- 448.0 pixels preoperatively and 1717.1 +/- 521.2 vs 1407.8 +/- 411.3 pixels at 6 months, P<.0001). At 6 months, contrast sensitivity log values were 1.62 +/- 0.31 and 1.78 +/- 0.34 for conventional and wavefront-guided LASIK eyes, respectively (P=.010). The visual complaint score was lower in the wavefront-guided LASIK group (P=.0116).
  
  
  CONCLUSIONS
  Compared to conventional ablation, wavefront-guided ablation provided superior outcomes in terms of postoperative glare under mesopic conditions, subjective complaints, and contrast sensitivity. In addition, it appears the glaremeter can be used for clinical quantitative evaluation of glare and halo.
authors.affiliation: Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea. shadik@yumc.yonsei.ac.kr
authors.forename: Hyung Keun
authors.initials: HK
authors.lastname: Lee
authors.forename: Chul Myung
authors.initials: CM
authors.lastname: Choe
authors.forename: Kyoung Tak
authors.initials: KT
authors.lastname: Ma
authors.forename: Eung Kweon
authors.initials: EK
authors.lastname: Kim
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000601:surgery; D015350:Contrast Sensitivity / Q000502:physiology*; D003623:Dark Adaptation; D003941:Diagnostic Techniques, Ophthalmological / Q000592:standards; D005260:Female; D019466:Glare; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D008027:Light; D008297:Male; D009216:Myopia / Q000601:surgery*; D011184:Postoperative Period; D011446:Prospective Studies; D011680:Pupil / Q000502:physiology; D015203:Reproducibility of Results; D016896:Treatment Outcome; D014792:Visual Acuity