Orthokeratology (OK) lenses are often prescribed to slow myopia progression in children. However, OK can have a perception of being unsafe for children, especially outside of primary eye care. If a patient is receiving conflicting recommendations from an optometrist and ophthalmologist, how can you bridge the gap to ultimately find the best solution for the patient?
In this post on the Myopia Profile group, RH is asking for advice on communicating with an ophthalmologist about orthokeratology, where it seems the ophthalmologist is against OK fitting in children.
Safety of orthokeratology
A real and valid concern about orthokeratology is the safety profile in children, and a key cause for objection. The most concerning complication of OK lens use is microbial keratitis (MK) as it can be sight-threatening infection.1
MK is typically associated with lack of practitioner and wearer training, improper fitting procedures, poor compliance to lens care and maintenance, and lack of routine follow up.2
An explosion of case reports of infections in childhood OK wear infections occurred in the early 2000's in East Asia, where these causative risk factors were wide spread, and resulted in the China Food and Drug Administration (FDA) commencing regulation of the practice of OK from 2002.3
Back in 2005, orthokeratology for myopic children was even termed a 'wolf in sheep's clothing'!4 Since then, though, an average of 50 peer-reviewed publications per year on orthokeratology has established its efficacy in both myopia correction and control, along with determining the incidence of complications.5
The safety of modern, regulated orthokeratology practice in children is around 1 per 1,000 patient wearing years,6 which is similar to the risk in reusable silicone hydrogel daily soft contact lens wear. Read more about this in Contact Lens Safety in Kids.
Efficacy of orthokeratology
Orthokeratology has been shown to be effective in slowing axial elongation in myopic children by around 50% over two years, according to meta-analyses.7-9
Discontinuation of OK wear before age 14 has shown a type of 'rebound' effect, although with axial growth similar to that of single vision spectacle lens wearers. Slower progression was again gained on resumption of OK wear after a period of cessation.10
Benefits of orthokeratology
Since orthokeratology lenses are effective in slowing axial length growth, reducing final level of myopia will also reduce a patient's lifelong risk of myopia-associated eye diseases like cataract, retinal detachment and myopic macular degeneration.
A comparison has been undertaken of the short-term risks of myopia controlling contact lens wear with the long-term risks of higher levels of myopia. Gifford's analysis on the Childhood and lifetime risk comparison of myopia control with contact lenses utilized peer reviewed data on contact lens safety in children and adults, alongside findings of the cumulative risk of vision impairment by age 75, based on axial length and level of myopia.11
When only 10 years of childhood CL wear was considered (age 8-17 inclusive), the likelihood of one case of MK (with 95% confidence intervals) was:
- 1 in 431 for daily disposable soft contact lenses (316, 511)
- 1 in 116 for reusable soft contact lenses (40, 517), and
- 1 in 67 for orthokeratology wear (19, 379).
Since the confidence intervals overlap, reusable SCLs and OK were concluded to be likely of a similar safety profile.
By comparison, the lifetime risk of vision impairment is:
- 1 in 18 for myopes of 3-6D (12, 39)
- 1 in 5 for myopes 6-10D (3, 12)
- 1 in 4 for axial lengths 26 to less than 28mm (2, 19)
If contact lens wear was commenced at age 8 for myopia control, and continued throughout life until age 65, the risk of MK of any type of contact lens wear is less than the lifetime risks of vision impairment from myopia-associated pathology when myopia is over 3D or axial length in excess of 26mm.11 This presents a clear case for the long-term benefits of wearing myopia controlling contact lenses like orthokeratology.
Regarding short-term benefits, OK is a very convenient method of vision correction for patients who engage in sport or have active lifestyles, as it eliminates reliance on optical correction during waking hours.
Orthokeratology can be combined with atropine
Combining orthokeratology with 0.01% atropine has shown an additive myopia controlling effect, compared to orthokeratology alone, in retrospective studies12 and newly published randomized clinical trials.13,14
Two year data indicated that the combined treatment slowed axial elongation by 0.18mm over two years in children who were 1-3D myopic at baseline, but had no significant effect for children who were 3-6D myopic at baseline, who progressed more slowly than the low myopes over the study. There was no effect of age - younger children didn't have a stronger effect than older children. The authors concluded that "combination therapy may be effective for slowing axial elongation, especially in children with low initial myopia."14
There is early data on combining multifocal soft contact lenses with 0.01% atropine,15 but at this stage orthokeratology is the only intervention for which efficacy in combination with atropine has been indicated.
How does RH’s story end?
It turns out that the ophthalmologist in question did not think orthokeratology would be unsuitable in general, but rather for this specific patient - his position was misunderstood or miscommunicated by a parent. This highlights the importance of maintaining open and respectful communication between ophthalmologists and primary eye care practitioners. In either case, it is ideal not to assume the reasons for another practitioners’ opposition or to be overly defensive. When communicating with an ophthalmologist about orthokeratology, remember that we are all on the same side - with the best interests of our patients being the key intention.
Take home messages:
- While there is a risk of microbial keratitis with orthokeratology use, it is relatively low, and can be managed through proper fitting processes, lens care and maintenance procedures and regular aftercare.
- Orthokeratology is an effective myopia control strategy, with the short-term and long-term benefits arguably outweighing the short-term risks. It is also the only intervention for which evidence exists of increased efficacy when combined with 0.01% atropine, especially for low myopes.
- Open lines of communication between eye care practitioners ensure the best chance for ideal patient outcomes.
- Hsiao CH, Lin HC, Chen YF, Ma DH, Yeh LK, Tan HY, Huang SC, Lin KK. Infectious keratitis related to overnight orthokeratology. Cornea. 2005;24(7):783-8. (link)
- Liu YM, Xie P. The Safety of Orthokeratology—A Systematic Review. Eye & Contact Lens. 2016;42(1):35-42. (link)
- China Food and Drug Administration. Orthokeratology Lens Fitting Operations Supervision Management Regulations 2001;326. (link)
- Kwok LS, Pierscionek BK, Bullimore MA, Swarbrick HA, Mountford J, Sutton G. Orthokeratology for myopic children: wolf in sheep's clothing? Clin Exp Optom. 2005;33: 343-347. (link)
- Bullimore MA, Johnson LA. Overnight orthokeratology. Cont Lens Anterior Eye. 2020;43(4):322-332. (link)
- Bullimore MA, Sinnott LT, Jones-Jordan LA. The Risk of Microbial Keratitis With Overnight Corneal Reshaping Lenses,. Optom Vis Sci 2013;90:937-44. (link)
- VanderVeen DK, Kraker RT, Pineles SL, Hutchinson AK, Wilson LB, Galvin JA, Lambert SR. Use of orthokeratology for the prevention of myopic progression in children: a report by the American Academy of Ophthalmology. Ophthalmol. 2019;126(4):623-36. (link)
- Si JK, Tang K, Bi HS, Guo DD, Guo JG, Wang XR. Orthokeratology for myopia control: a meta-analysis. Optometry and Vision Science. 2015;92(3):252-7. (link)
- Sun Y, Xu F, Zhang T, Liu M, Wang D, Chen Y, Liu Q. Orthokeratology to control myopia progression: a meta-analysis. PloS one. 2015;10(4):e0124535. (link)
- Cho P, Cheung SW. Discontinuation of orthokeratology on eyeball elongation (DOEE). Contact Lens and Anterior Eye. 2017;40(2):82-7. (link)
- Gifford KL. Childhood and lifetime risk comparison of myopia control with contact lenses. Cont Lens Anterior Eye. 2020;43(1):26-32. (link)
- Chen Z, Huang S, Zhou J, Xiaomei Q, Zhou X, Xue F. Adjunctive effect of orthokeratology and low dose atropine on axial elongation in fast-progressing myopic children—a preliminary retrospective study. Contact Lens and Anterior Eye. 2019 Aug 1;42(4):439-42. (link)
- Tan Q, Ng AL, Choy BN, Cheng GP, Woo VC, Cho P. One‐year results of 0.01% atropine with orthokeratology (AOK) study: a randomised clinical trial. Ophthalmic Physiol Opt. 2020;40(5):557-66. (link)
- Kinoshita N, Konno Y, Hamada N, Kanda Y, Shimmura-Tomita M, Kaburaki T, Kakehashi A. Efficacy of combined orthokeratology and 0.01% atropine solution for slowing axial elongation in children with myopia: a 2-year randomised trial. Sci Rep. 2020;10(1):12750. (link)
- Huang J, Mutti DO, Jones-Jordan LA, Walline JJ. Bifocal & Atropine in Myopia Study: Baseline Data and Methods. Optom Vis Sci. 2019;96(5):335-344. (link)