title: Prospective, randomized, fellow eye comparison of WaveLight Allegretto Wave Eye-Q versus VISX CustomVueTM STAR S4 IRTM in photorefractive keratectomy: analysis of visual outcomes and higher-order aberrations.
abstract: BACKGROUND
  The purpose of this study was to compare differences in visual outcomes, higher-order aberrations, contrast sensitivity, and dry eye in patients undergoing photorefractive keratectomy using wavefront-guided VISX CustomVue™ and wavefront-optimized WaveLight(®) Allegretto platforms.
  
  
  METHODS
  In this randomized, prospective, single-masked, fellow-eye study, photorefractive keratectomy was performed on 46 eyes from 23 patients, with one eye randomized to WaveLight Allegretto, and the fellow eye receiving VISX CustomVue. Three-month postoperative outcome measures included uncorrected distance visual acuity, corrected distance visual acuity, refractive error, root mean square of total and grouped higher-order aberrations, contrast sensitivity, and Schirmer's testing.
  
  
  RESULTS
  Mean values for uncorrected distance visual acuity (logMAR) were -0.03 ± 0.07 and -0.06 ± 0.09 in the wavefront-optimized and wavefront-guided groups, respectively (P = 0.121). Uncorrected distance visual acuity of 20/20 or better was achieved in 91% of eyes receiving wavefront-guided photorefractive keratectomy, and 87% of eyes receiving wavefront-optimized photorefractive keratectomy, whereas uncorrected distance visual acuity of 20/15 was achieved in 35% of the wavefront-optimized group and 64% of the wavefront-guided group (P ≥ 0.296). While root mean square of total higher-order aberration, coma, and trefoil tended to increase in the wavefront-optimized group (P = 0.091, P = 0.115, P = 0.459, respectively), only spherical aberration increased significantly (P = 0.014). Similar increases were found in wavefront- guided root mean square of total higher-order aberration (P = 0.113), coma (P = 0.403), trefoil (P = 0.603), and spherical aberration (P = 0.014). There was no significant difference in spherical aberration change when comparing the two platforms. The wavefront-guided group showed an increase in contrast sensitivity at 12 cycles per degree (P = 0.013).
  
  
  CONCLUSIONS
  Both VISX CustomVue and WaveLight Allegretto platforms performed equally in terms of visual acuity, safety, and predictability in photorefractive keratectomy. The wavefront-guided group showed slightly improved contrast sensitivity. Both lasers induced a comparable degree of statistically significant spherical aberration, and tended to increase other higher-order aberration measures as well.
authors.affiliation: University of Utah, John A Moran Eye Center, Department of Ophthalmology and Visual Sciences, Salt Lake City, UT, USA.
authors.forename: Majid
authors.initials: M
authors.lastname: Moshirfar
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Churgin
authors.forename: Brent S
authors.initials: BS
authors.lastname: Betts
authors.forename: Maylon
authors.initials: M
authors.lastname: Hsu
authors.forename: Shameema
authors.initials: S
authors.lastname: Sikder
authors.forename: Marcus
authors.initials: M
authors.lastname: Neuffer
authors.forename: Dane
authors.initials: D
authors.lastname: Church
authors.forename: Mark D
authors.initials: MD
authors.lastname: Mifflin