As early as the 1940’s, Dr.’s and contact lens technicians discovered the
“moulding” effects resulting from glass scleral contact lenses. However, there
was a lot of confusion as to exactly what was happening.
Following the advent of “corneal” contact lenses in the 1950’s, NERF
optometrists theorized that this corneal moulding phenomenon could be
potentially positive to patients if the effect could be achieved in a safe and
George Jessen is credited with the first OK design he called “ortho-focus” in
early 1960’s using PMMA material. Shortly after, Newton Wesley coined the term
“orthokeratology”. This early therapy required multiple modifications over a
period of months to achieve maximum effect. The results tended to be
unpredictable which resulted in the belief that ortho-keratology was
The International Orthokeratology Section (IOS) of NERF was born in 1968 and
to date this section continues to be the main platform for information exchange
and publication regarding orthokeratology. (Website LINK)***
In the late 1970’s, with the advent of rigid gas permeable materials, larger
lens designs were used for better centration and results. These materials
greatly increased safety and efficacy both for conventional wear and
orthokeratology. Several studies concluded at this time that the risk of
complications for orthokeratology was no higher than conventional contact lens
wear. Still, there continued to be concerns of “corneal warpage”, poor
reproducibility, predictability, length of time for treatment and awareness of
this day-wear lens now that soft contact lenses had been introduced.
Orthokeratology was brought back into the spotlight in the late 80’s and
early 90’s with the advent of computer numerically controlled lathes and the
resultant development of the reverse geometry OK lens. Many persons lay claim
to having theorized or developed the first RG design OK lens, but it is
generally held that Richard Wlodyga, OD was the father of the modern AOK lens.
Although these lenses were originally prescribed as a daywear modality, reports
of nightwear therapy started to emerge in as early as 1993.
Throughout the 90’s, numerous companies developed 3,4 and 5 curve reverse
geometry lens designs with spherical, aspheric and tangential periphery designs.
The term “Accelerated Ortho-Keratology” (AOK), emerged to describe reverse
geometry OK fitting and is used to separate the original 1960’s-70’s O.K. from
modern or advanced OK therapy. AOK was a major advancement in the field as it
“accelerated” the OK effects from months and numerous lenses to days and limited
lenses per eye.
Most, if not all historical OK designs and modern AOK lenses are based on
the Jessen formula. The theory assumes that there is a linear relationship
between myopia reduction and base curve selection. In other words, if the
cornea had a flat K reading of 42.00D and an Rx of –2.00D, you fit a 40.00D base
curve which would change the corneal curvature and therefore the refraction by
the required amount. This formula has been varied some but is principally in
use today in the determination of all AOK lens parameters.