ORTHO-K: A Myth or A Fact?

Reshaping the cornea with contact lenses to improve vision isn’t new. Orthokeratology has been practiced by some eye doctors for decades. 

 

(http://www.osa.net.au/aboutok.php#history)

The concept of ORTHO-K was introduced by Dr. George Jessen in 1962. He delivered his new method for myopia reduction to the 2nd International Congress for Contact Lenses in Chicago.Since then researchers and academics including institutes like UC Berkeley (The Berkeley Orthokeratology Study, 1983), UC Sandiego and University of Houston have started to advance technology and better understanding of the criteria needed to successfully practice ORTHO-K for a predictable and effective result.

The three main breakthroughs that gave ORTHO-K a ‘rebirth’ were the invention of highly oxygen permeable material, a new reverse-geometry design and the prevalence of corneal topography in 1980s. In result ORTHO-K was approved by FDA in 1994 and then 2002 for overnight use.

In terms of material of contact lenses, there are two types: Rigid (hard) and Soft. Soft lens has been popular since its creation in 1971. But the first contact lens invented was made from hard material in 1948, PMMA, with an original intention to treat irregular corneas, for example, keratoconus.  Rigid gas permeable (RGP) lenses is a type of rigid contact lens, and it is the material used in ORTHO-K.

These materials allowed significant transmission of oxygen to the cornea during closed-eye lens wear and were used successfully and safely for extended wear in conventional lens designs. (Swarbrick, Orthokeratology Review and Update)

In fact, Food and Drug Administration in the USA has set strict requirements to contact lenses. It is safe to wear certain contact lenses overnight when they are approved for extended wear.  Extended wear is not new but less common in Pakistan, the extended wear for soft lenses and rigid lenses was approved by FDA in USA in 1981 and 1987. (http://www.contactlenses.org/timeline.htm) The leading contact lens manufacturing company, Bausch+Lomb, produces both types of contact lenses.

The reverse-geometry lens, designed by Richard Wlodyga and Nick Stoyan accelerated the process of ORTHO-K in early 1990s.

These pioneers described a novel OK lens design that they reported to induce rapid changes in myopic refractive error, within days to weeks, without the problems associated with poor lens centration. The development of sophisticated computer controlled lathing methodologies at about this time allowed easy fabrication of these new relatively complex reverse geometry lens designs. (Swarbrick, Orthokeratology Review and Update)

The prevalence of corneal topography also provided evidence to assure the safety of this non-surgical method that ORTHO-K does harm or distort cornea, and rather it temporarily redistribute cells of cornea which is highly elastic in nature.

The effectiveness and safety for overnight use of ORTHO-K is approved in 2002. Information of ORTHO-K is available on U.S. Food and Drug Administration.

FDA1

Similarly, Ortho-k is a recognized treatment in UK, information can be found on government’s National Health Service website.

uk

With practices in more than 30 countries in the world, do you still think it is a gimmick?

From the information gathered from Orthokeratology Society of Oceania (OSO), European Academy of Orthokeratology, Orthokeratology Academy of America ORTHO-K is practiced in at least 30 countries by thousands of optometrists or ophthalmologists.

Estimates of worldwide usage of overnight OK have not been published. At the 2005 Global Orthokeratology Symposium (GOS) in Chicago, Jacobson reported that current usage was highest in East Asia, particularly in children and adolescents, and estimated that more than 150,000 patients were wearing this modality in the region. Reportedly, up to 80,000 patients have been fitted in the USA,1910,000 in the Netherlands18and more than 3,500 in Australia.20  (Swarbrick, Orthokeratology Review and Update)

Keeping in mind the report was made in just three years after the approval of FDA, the trend of ORTHO-K can be shown by the increasing number of ORTHO-K practitioners.

Many clinical researches have been done to investigate and support the efficacy and safety of ORTHO-K practice. In which the more famous researches are Children’s Overnight Orthokeratology Investigation(2008) by Jefferey J Walline et al. The Ohio State University College of Optometry, The Longitudinal Orthokeratology Research in Children by Pauline Cho et al. Department of Optometry & Radiography, The Hong Kong Polytechnic University  Retardation of Myopia in Orthokeratology (ROMIO) StudyA 2-Year Randomized Clinical Trial(2012) by  Pauline Cho et al. Department of Optometry & Radiography, The Hong Kong Polytechnic University. And An Update on Orthokeratology by Cary M. Herzberg, OD, FOAA

The effect of ORTHO-K takes place from the first day but the procedure of ORTHO-K involves 8 to 10 visits to the clinic. Sometimes the lens fitting needs to be changed if it is observed to be tight or loose in any of the visit.  ORTHO-K procedure is carefully monitored in the time span of 4-6 months to prevent any complication or risk. Every lens of ORTHO-K lens is customized, hence it cannot be ordered online.

In summary, ORTHO-K is an established and mature practice in the world. This wonderful non-surgical treatment for myopia reduction is achieved by decades of hard work.