Orthokeratology has been studied for a long time. Several studies have been done on the safety and effectiveness of ortho-k. Today ortho-k is FDA approved, very safe, and very effective for your eyes in changing your myopia. Below are a few studies conducted on orthokeratology.
CLAMP (Contact Lens and Myopia Progression)
The CLAMP study began as a way to study the efficacy of using rigid contact lenses to treat myopia in young children as well as determine the mechanism of the treatment if treatment is useful. The study was also used to compare issues of vision and comfort between rigid and soft contact lens wearers. At the end of the study it was found that rigid gas permeable lenses slow the progression of myopia in small children more than soft lenses. However, the decreased refractive error does not also mean that the axial growth is slowed. The study also indicated that the change in corneal curvature is reversible, and is most effective in the first year of use.
Myopia Control (Houston Study)
This study investigated controlling myopia progression with rigid gas permeable contact lenses versus eyeglasses. Studies showed that those who wore eyeglasses has an increase in myopia of .78 D per year, whereas using gas permeable lenses slowed progression to .42 D per year. The study also showed more axial growth in those that wore eyeglasses than those that wore GP lenses. Thus the decrease in progression of myopia is stronger in GP lenses because of axial length growth reduction and corneal flattening.
LORIC (The Longitudinal Ortho-k Research in Children)
This is another study that was designed to investigate whether or not orthokeratology can effectively reduce and control myopia in young children, by comparing lens use to eyeglasses use. The study monitored growth of axial length, vitreous chamber depth, corneal curvature, and relationships with changes of refractive errors. The study indicated that those who used orthokeratology at night, found that their vision was improved and acceptable throughout the day. The study also showed that those with a higher myopia prescription show a better decline in progression than those without.
SMART (Stabilizing Myopia by Accelerating Reshaping Technique)
This study focused on the idea that orthokeratology lenses can be worn effectively at night to slow progression of myopia in children. The study focused on children that were eight to eleven years old. The study compares children wearing soft lenses during the day to children wearing orthokertaology lenses at night.