Stability of wavefront aberrations during the daytime after 6 months of overnight orthokeratology corneal reshaping

J Refract Surg. 2007 Nov;23(9):978-83. doi: 10.3928/1081-597X-20071101-21.

Abstract

Purpose: To evaluate the stability of wavefront aberrations during the daytime after 6 months of overnight orthokeratology corneal reshaping.

Methods: A prospective study of 26 eyes using the Ultravision BE lens design during 6 months of overnight wear. Uncorrected visual acuity (UCVA), cycloplegic refraction, and wavefront aberrometry were measured at 8 AM (within 1 hour after awakening and removing lenses), 1 PM (5 to 6 hours after lens removal), and 6 PM (10 to 12 hours after lens removal).

Results: There was no significant difference in UCVA between 8 AM, 1 PM, and 6 PM (P=.383). Spherical power from wavefront aberrometry showed significant regression from 8 AM to 1 PM (P<.001) and stabilized near zero diopters. Total root-mean-square (RMS) increased and higher order aberration RMS and defocus (Z4) decreased between 8 AM and 1 PM (P<.001) but did not change for the rest of the day (P>.001). There was no statistically significant change in astigmatism (Z3 and Z5) (P=.449) and coma (Z7 and Z8) (P=.145) between 8 AM, 1 PM, and 6 PM. Spherical aberration (Z12) showed regression throughout the day (P<.001).

Conclusions: After 6 months of overnight orthokeratology wear, some optical aberrations showed regression during the day. Despite no significant change in UCVA during 10 to 12 hours, there was a significant increase in defocus (Z4) within the first 5 hours after removing the orthokeratology lens and a decrease in spherical aberration (Z12) throughout the day.

MeSH terms

  • Circadian Rhythm*
  • Corneal Topography
  • Diagnostic Techniques, Ophthalmological*
  • Fixation, Ocular
  • Humans
  • Orthokeratologic Procedures*
  • Prospective Studies
  • Refraction, Ocular
  • Refractive Errors / diagnosis*
  • Refractive Errors / physiopathology
  • Refractive Errors / therapy*
  • Time Factors
  • Visual Acuity