Empirical advanced orthokeratology through corneal topography: The University of Houston clinical study

Sami El Hage, Norman E. Leach, William Miller, Thomas C. Prager, Jason Marsack, Katrina Parker, Angela Minavi, Amber Gaume

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


PURPOSE. Traditionally, orthokeratology has used diagnostic lenses to determine the best fit. The purpose of this study was to determine the efficacy of fitting empirically from corneal topography, without the use of diagnostic lenses. METHODS. Twenty-nine subjects, 18 to 37 years old, with myopia of 1.00 to 4.00 diopters (D) and astigmatism of no more than 1.50 D, were entered into this 6-month study. Corneal topography, scanning slit topography and corneal thickness (Orbscan), confocal microscopy, ultrasound corneal thickness, aberrometry, and biomicroscopy were used to assess corneal changes. Unaided logMAR high-contrast visual acuity, subjective refraction, and questionnaires were used to monitor vision and symptoms. Follow-up visits were scheduled after 1 day, 1 week, 2 weeks, 1 month, 3 months, and 6 months. RESULTS. For 6-month data, unaided logMAR acuity improved from 0.78 ± 0.26 in the right eye and 0.75 ± 0.22 in the left eye to 0.06 ± 0.18 in the right eye and 0.04 ± 0.16 in the left eye. Myopia decreased from -2.55 ± 0.87 D in the right eye and -2.47 ± 0.89 D in the left eye to +0.45 ± 0.74 D in the right eye and -0.17 ± 0.69 D in the left eye. Shape factor, using corneal topography, increased from 0.85 ± 0.13 in the right eye and 0.85 ± 0.15 in the left eye to 1.28 ± 0.32 in the right eye and 1.30 ± 0.29 in the left eye. Both eyes showed a decrease in lower-order aberrations (i.e., defocus) and an increase in higher-order aberrations (i.e., spherical aberrations and coma). CONCLUSIONS. Myopia reduction after 1 week was clinically insignificant from the 1-month results, indicating that the full effect is achieved by 1 week. Neither total nor epithelial corneal thickness varied significantly from baseline measurements.

Original languageEnglish (US)
Pages (from-to)224-235
Number of pages12
JournalEye and Contact Lens
Issue number5
StatePublished - Sep 2007


  • Confocal microscopy
  • Corneal topography
  • Optical aberrations
  • Optical pachymetry
  • Reverse geometry

ASJC Scopus subject areas

  • Ophthalmology


Dive into the research topics of 'Empirical advanced orthokeratology through corneal topography: The University of Houston clinical study'. Together they form a unique fingerprint.

Cite this