The Berkeley Orthokeratology Study, Part II: Efficacy and duration

Area of Science:

• Ophthalmology
• Optometry
• Vision Science

Background:

• Myopia management is a growing concern in optometry.
• Orthokeratology offers a non-surgical approach to myopia control.
• Understanding the long-term efficacy and stability of orthokeratology is crucial.

Purpose of the Study:

• To evaluate the relative efficacy of orthokeratology (OK) in reducing refractive error and improving visual acuity.
• To assess changes in corneal curvature associated with OK lens wear.
• To determine the duration of refractive changes and their stability after discontinuing lens wear.

Main Methods:

• A randomized controlled study comparing orthokeratology (31 subjects) with conventional rigid contact lenses (28 subjects).
• Measurements included refractive error, unaided visual acuity (logMAR), and corneal curvature.
• Subjects were monitored during lens wear and after discontinuation to assess reversibility.

Main Results:

• Orthokeratology resulted in a mean spherical equivalent reduction of 1.01 D versus 0.54 D in controls after 444 days (p=0.02).
• Improvements in unaided visual acuity were observed in both groups.
• Refractive changes were largely achieved within 132 days, with minimal additional change thereafter. Rebound to baseline occurred within 95 days of lens removal.

Conclusions:

• Orthokeratology can achieve a myopia reduction of approximately 1 diopter.
• The refractive changes induced by orthokeratology are not permanent and are reversible upon lens removal.
• Vision stability during non-lens wear periods is questionable, impacting the predictability of vision under retainer lens wear programs.