July 2021
Column
The Myopia Mortgage
A lot has been said about myopia management in our field. If anything, it is a huge upgrade for our small specialty lens 'niche' arena to a 'not-so-niche-anymore' field, with multinationals in the global contact lens arena affiliating with and purchasing specialty contact lens labs. What a game changer! And a nice confirmation of and, really, compliment of the fact that 'we were not crazy', although sometimes it felt a bit that way. While increasing in interest, the attitude from the ECP point of view remains divided. Many possible causes for this have been raised, but the biggest one in my view is this: timing. While we are talking to 6-,7- and 8-year-olds (and their parents) in our chair about putting lenses on their eyes, changing the shape of their cornea - with corneal risks, hassle and costs involved - we have to balance all of that against an increased risk of myopia-related pathology...in 40 years from now in the lifetime of that kid. That is like taking out a long-term mortgage. With COVID-19, we have seen that people act when there is a direct threat. But with things like global warming or myopia...that is a problem and a concern over the long term, which is much harder to communicate.
Myopia
Myopia Prescribing
Sheila Morrison writes in Review of Myopia Management about ‘Prescribing’ Myopia Management. 'Prescribing' lifestyle and other interventions could indeed underscore the seriousness of the myopia disease down the line for a patient. This also puts the (pre-) myope at the center of attention: it is about prescribing the best intervention method for thát particular child, which could be anything (certainly not limited to ortho-k or even to contact lenses). 'Prescribing' more outdoor time, less indoor time and less near work activity should also be included. In line with the previous item in this newsletter, Sheila quotes: 'It is imperative to articulate to the parent that myopia management is long term and that you’re in it together with the child.' Amen to that.
Stopping Myopia Treatment
Rebecca Yan Shun Weng in Review of Myopia Management touches on the delicate topic of when and how myopia management treatment should be discontinued. The decision to stop myopia treatment at any given point requires as much consideration as the treatment initiation, Rebecca writes. Treatment cessation may be best carried out when the myopia progression rate slows, which is usually when the child reaches late adolescence. However, close monitoring is mandatory in managing these patients. If acceleration in myopia progression is detected, immediate recommencement of treatment is required. For more, see link below.
AXL vs. SE - or both?
Thomas Naduvilath from the Brien Holden Vision Institute and the School of Optometry and Vision Science at the UNSW (AU) asks the question of what method is best to measure myopia progression: spherical equivalent refraction (SE), axial length (AXL), or both? SE alone doesn't mean much; as an example, he discusses a Caucasian -0.50D child aged 8 years, whom without myopia control is estimated to progress to -1.10D at 9 years and -1.60D at 10 years of age. In other words, the progression is -0.60D and -0.50D for the first and second years, respectively. This may then be used to compare the individual’s observed progression, in which progression is measured as change in SE from the starting age (in this case, age 8). “Absolute efficacy” is the observed difference minus the expected difference in SE progression. “Efficacy %” is the absolute efficacy divided by the expected progression. A negative percentage indicates the efficacy of myopia treatment. The Efficacy % can be compared to published data and tracked over time. For AXL, there is clear evidence that the rate of AXL change can be a strong predictor of the risk of myopia. At an individual level, this is easily computed by recording the AXL at each follow-up examination. An example for a child aged 8 years is provided, who was hyperopic at baseline and became myopic. The observed annual AXL change is compared to the published data of 0.1mm and 0.2mm for non-myopes and myopes, respectively. The “Efficacy %” in this case is computed as the absolute difference divided by the expected elongation, which can be tracked over time. A negative percentage indicates myopia treatment efficacy. In conclusion: in evaluating the efficacy of myopia management strategies, there should be confidence that the treatment is efficacious at an anatomical level (slows growth) and provides functional outcomes (vision). 
Near Work Activity Interruptions
Researchers at the Queensland University of Technology in Brisbane (AU) delivered another excellent piece of work that looked at the effect of interrupting blurred vision with periods of clear vision, which may have implications for understanding myopia development and its prevention. Brief periods of clear vision can diminish axial elongation and choroidal thinning induced by hyperopic defocus exposure in human eyes, they found. The right eyes of 16 young adults were exposed to 60min episodes of continuous and interrupted defocus conditions (+3DS and −3DS) over five separate sessions, with the left eye optimally corrected for distance. For interrupted defocus, 2min episodes of clear vision were imposed before each 15min episode of myopic or hyperopic defocus (2/15 min). For hyperopic defocus, the effect of frequency of clear vision exposure was also assessed by imposing 1min of clear vision before each 7.5min of defocus (1/7.5 min). After 60min of continuous hyperopic defocus, the eye elongated significantly by 9±9μm. When exposed to interrupted (2/15 min) hyperopic defocus, axial elongation was significantly reduced by 77% compared to with continuous hyperopic defocus, with a final change of only 2±10μm relative to baseline. During interrupted (1/7.5 min) hyperopic defocus, axial elongation reduced slightly compared to continuous hyperopic defocus (6±8μm relative to baseline. A similar pattern of response was observed for choroidal thickness changes with continuous and interrupted (1/7.5 min) hyperopic defocus conditions. If hyperopic defocus contributes to myopia progression in humans, then interruption with brief periods of clear (e.g. distance) vision could reduce its myopiagenic effects, the authors conclude.
Image: Siora Photography
Managing the Pre-Myope
In the IMI white papers it is stated that if your patient has less hyperopia than expected for their age, with any of the risk factors below, then you can consider him or her to be pre-myopic. Risk factors are: 1) Ethnicity – there is a higher prevalence of myopia in certain ethnic groups, and East and Southeast Asians have a higher prevalence of myopia compared with Europeans, Africans, and Indians. 2) Parental myopia – one myopic parent increases the risk three times, and two myopic parents increase the risk six times. 3) Reduced time outdoors and increased near work – clinical trials have reported that increasing additional time outdoors to at least 120 minutes per day is protective against new cases of myopia, while intense near work is associated with increased risk of myopia. 4) Urban environment – those living in dense cities tend to have a higher risk than do those in rural or suburban settings, as urban environments are linked to less time spent outdoors and more near work activity. Currently, there is no strong evidence to start optical and pharmacologic treatments in a pre-myope: for now, it is advised to promote increased time outdoors of at least 80 minutes daily (with sun protection) and reduced near work to less than 2.5 hours per day.
Combination Therapy - OK & Atropine
The purpose of this study was to analyze the one-month change in subfoveal choroidal thickness of myopic children treated with 0.01 % atropine, orthokeratology (OK), or their combination. One hundred fifty-four children aged between 8 and 12 years with a spherical equivalent of -1.00D to -6.00D were enrolled. Choroidal thickness significantly increased in the group using combined therapy (14.12 ± 12.88 μm), in the OK group (9.43 ± 9.14 μm) and in the atropine group (5.49 ± 9.38 μm), while it significantly decreased in the control group (-4.81 ± 9.93 μm). In conclusion: the combination of OK and atropine induced a greater increase in choroidal thickness compared to monotherapy with atropine, which might indicate a better treatment effect for childhood myopia control.
Myopia
I-site is an educational newsletter that is distributed on a monthly basis and provides an update on rigid gas permeable-related topics (scientific research, case reports and other publications worldwide). I-site is objective and non-political. Disclosure: I-site's editor Eef van der Worp, optometrist PhD FAAO FBCLA FIACLE FSLS, receives educational grants from a number of industry partners but is not related to any specific company.