A closer look at how OrthoK reshapes the cornea, the decades of research behind it, and how treatment differs depending on your prescription.
OrthoK has been refined for over 60 years — but it's the last two decades of rigorous clinical research that transformed it into a leading myopia control treatment.
Optometrist George Jessen introduces "Orthofocus" lenses, the earliest form of orthokeratology — observing that fitting rigid lenses flatter than the cornea could temporarily reduce myopic refractive error.
Advances in lens lathing technology allow the development of the first reverse geometry lens designs, generally credited to Dr Richard Wlodyga and Nick Stoyan — laying the foundation for modern OrthoK.
Computerised corneal topography makes precise, repeatable lens designs possible for the first time, while new high-oxygen-permeability lens materials make safe overnight wear achievable — giving rise to modern "accelerated" OrthoK.
Research shifts from vision correction alone to myopia control. Landmark studies — including Professor Pauline Cho's LORIC, ROMIO and TO-SEE trials at the Hong Kong Polytechnic University — provide robust clinical evidence that OrthoK meaningfully slows myopia progression in children.
Much of today's evidence for OrthoK as a myopia control treatment comes from the work of Professor Pauline Cho and her team at the Hong Kong Polytechnic University. Her ROMIO study (Retardation of Myopia in Orthokeratology) — a two-year randomised controlled trial published in Investigative Ophthalmology & Visual Science — found that children wearing OrthoK lenses had significantly slower eye elongation than those in glasses, with the youngest children showing the greatest protective effect.
Her related TO-SEE study extended these findings to children with astigmatism using toric OrthoK lenses, while a 2017 reanalysis of both trials confirmed that OrthoK meaningfully reduces the risk of rapid myopia progression, particularly in children aged 6–8. This body of research remains some of the most cited evidence in the myopia management field. Search "Pauline Cho orthokeratology" on PubMed to explore the published literature yourself.
OrthoK lenses look nothing like standard contact lenses — and that difference is exactly what makes reshaping the cornea possible.
Unlike a standard contact lens, which simply follows the curve of your cornea, an OrthoK lens uses a specialised reverse geometry design. Its base curve is deliberately fitted flatter than your cornea centrally, with a steeper "reverse" curve in the mid-periphery — the opposite curvature relationship to a conventional lens.
This shape creates a thin layer of tears trapped between the lens and your eye — thicker in the mid-periphery, thinner centrally. As you sleep, this tear film generates gentle fluid forces, combined with light pressure from your eyelid, that redistribute the outer layer of corneal cells. The result is a precise, temporary reshaping of your central cornea's curvature — with no cutting, no permanent tissue change, and no surgery involved.
Because myopia and hyperopia are optically opposite problems, the lens design needed to correct each is opposite too.
In myopia, light focuses in front of the retina because the cornea is too steep (or the eye too long). The OrthoK lens gently flattens the central cornea, reducing its focusing power so light lands precisely on the retina — sharpening distance vision.
In hyperopia, light focuses behind the retina because the cornea is too flat for the eye's length. Here, the lens design is essentially inverted — it steepens the central cornea instead, increasing focusing power so light converges correctly on the retina.
Astigmatism happens when the cornea is more curved along one meridian than the perpendicular one — shaped more like a rugby ball than a sphere — which scatters light into two separate focal points instead of one.
A standard, symmetrical OrthoK lens can struggle to centre well on a significantly astigmatic cornea. That's where toric (or dual axis) OrthoK lenses come in — designed with two different curves on the back surface, precisely aligned to the orientation of your corneal astigmatism. This allows controlled, even reshaping across both meridians simultaneously, correcting astigmatism alongside short- or long-sightedness in the one lens.
However complex the science, the routine itself couldn't be easier.
Pop your custom OrthoK lenses in as part of your normal bedtime routine — just like regular contacts.
While you sleep, gentle fluid forces reshape your cornea. No effort required — the treatment happens overnight.
Remove your lenses in the morning and enjoy clear vision all day — no glasses, no daytime contacts.
Book a comprehensive assessment and we'll map out exactly what treatment would look like for your eyes.