This meta-analysis investigated the effectiveness of orthokeratology in controlling the progression of anisomyopia (unilateral myopia or bilateral anisomyopia) in Chinese children. Total anisomyopia decreased at 2-year follow up, indicating orthokeratology may be a safe clinical method to slow myopia progression coupled with reducing interocular axial length difference.
This meta-analysis of 5 studies of 1, 6 and 12 months duration found that slower axial growth is evident when using orthokeratology in conjunction with atropine as a combined therapy compared to orthokeratology alone. A slowing effect of 0.09mm was seen with the combined approach for up to a 12 month follow-up period. Longer data was not available for the meta-analysis.
The risk of microbial keratitis (MK) in orthokeratology-wearing children was shown in a 2013 analysis to be around 14 per 10,000 patient wearing years, but new data indicates that it may be lower. Data gathered from a large group of practices in Russia found MK risk of around 5 per 10,000 patient-wearing years, similar to the risk of daily wear soft lenses. This should increase confidence in fitting orthokeratology to children for myopia control.
A sample of slow and fast progressors in prior 24 month orthokeratology clinical trials were found to have the same baseline refraction and axial length. The slow progressors were older, and showed 0.5mm smaller treatment zone diameters (TZDs), but no difference in induced peripheral myopic shift. There was also no direct correlation between TZD and axial elongation, indicating an intriguing but not yet defined relationship.
This study evaluates how orthok treatment zone diameter influences change in refraction and axial eye length over 1-year in children previously fit with orthok lenses of varying back optic zone diameter, to reveal that where treatment zone diameter was less than pupil diameter orthok’s myopia control efficacy appeared to be improved.
Prototype soft CLs designed to replicate the optical profile induced by OK were found to provide similar whole eye wavefront aberration measurements at distance and near fixation to existing OK lens wearers.
Soft contact lenses designed to simulate the change in refraction optical pro-file from orthokeratology (OK) fail to slow axial eye elongation or change to refrac-tion over 1-year of wear in children, leading to suggestion that OK’s propensity to slow myopia progression may not be due to changes OK makes to optical profile.
This research investigated orthokeratology lenses designed for a higher peripheral ‘add’ power, and how these influenced corneal hysteresis (rigidity) and higher order aberrations.
Understanding how orthokeratology alters ocular aberrations helps to understand research and potential mechanisms of myopia control. Here we explain more.
Welcome to the final instalment of myopia content from the American Academy of Optometry 2019 meeting. These updates continue from Part 2, which detailed Mark Bullimore and Noel Brennan’s fantastic session entitled Twelve Evidence Based Things That We Should Know About Myopia.
