Purpose
To examine the efficacy and reliability of anterior segment OCT (AS-OCT) in guiding specialty contact lens (CL) fitting in guinea pig eyes. Small-scale clinical studies suggesting that orthokeratology (Ortho-K) is effective in controlling myopia progression motivated this study, with our longer term goal being to use the myopic guinea pig model to better understand the mechanism underlying myopia retardation with Ortho-K.
Methods
Six guinea pigs underwent unilateral Ortho-K fitting with their contralateral eyes serving as controls. Corneal topography, refraction, biometric axial ocular parameters were assessed to aid in the design of the Ortho-K lenses; measurements were made every day, starting on the day of initial lens fitting until the corneal reshaping effect has stabilized. The anterior segment was assessed with and without fluorescein staining by slit lamp biomicroscopy and photographically recorded; AS-OCT imaging was used to monitor corneal integrity, CL stability, and the progress of corneal reshaping.
Results
On average, extended wear (EW) Ortho-K lenses could induce more than 6 diopters of central corneal flattening and corresponding paracentral steepening without significantly affecting corneal integrity and/or the stability of the lens fitting. There was less corneal fluorescein staining in the eyes with EW Ortho-K lenses, comparing to the non-lens wearing eye. AS-OCT imaging significantly reduced the frequency of lens reordering.
Conclusions
The combination of AS-OCT imaging and corneal topography provided the essential information for designing and fitting Ortho-K lenses to this animal model. The EW OrthoK modality applied to guinea pig eyes allows for corneal reshaping similar to its clinical application. Further study of Ortho-K in this application may yield important insight into the mechanism underlying its myopia control effect.
Keywords: 477 contact lens •
605 myopia •
677 refractive error development