Science

Orthokeratology

Blur adaptation in children wearing orthokeratology

After 1 month of wearing orthokeratology lenses, children were shown to have reduced accommodative lag and increased blur sensitivity, leading to the suggestion that blur adaptation is conducive in achieving good visual acuities and visual function in ortho-k wear.

Can we predict success with orthokeratology?

This study investigated the accuracy of using pre-treatment axial elongation and changes in refractive sphere in predicting myopia control success in orthokeratology. Axial length was the more accurate method for categorisation of slow, moderate or rapid progression, and fast progressors benefited the most from ortho-k wear.

Atropine 0.01% combined with orthokeratology over two years

Atropine 0.01% combined with orthokeratology slows axial elongation to less than 0.1mm/year over two years in Chinese children aged 6-11 years. This is the equal-longest study on this topic and first to measure potential mechanisms of pupil size and choroidal thickness. The largest effect of the combination occurred in the first 6 months.

Can orthokeratology be used to slow the progression of anisomyopia?

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. 

Can using atropine enhance myopia control with orthokeratology?

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.

How common is microbial keratitis in children wearing orthokeratology?

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.

Orthokeratology treatment zone diameter in slow and fast progressors

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.

Influence of orthok treatment zone diameter and pupil diameter on myopia progression

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.