Speaking at conferences in Australia, New Zealand, Europe and America on myopia control has seen numerous practitioners clearly interested in my approach to myopia management. The difficulty in the busy clinician translating research into practice is that full spectrum myopia management demands knowledge of epidemiology, optics, specialty contact lenses and binocular vision. That’s a lot to get your head around, so let me help you! Here are eight ways to get your myopia management practice firing.
Change involves numerous small steps, so start with one a week to integrate these evidence based approaches into your practice. Soon your patients will be referring their friends and family for the same comprehensive treatment.
1. Talk to myopic parents about risks for their children. One myopic parent increases a child’s risk of developing myopia by 2-3 times, and this doubles for two myopic parents.(1) It’s likely that the highly myopic parent is bringing their child in to see you for this very reason, but if the presenting complaint isn’t related (for example ocular allergies or learning difficulties), ensure you get an understanding of their refractive history to best manage their child.
2. Watch for the lower-than-average hyperopes. One of the biggest risks for myopia development, independent of ethnicity and family history, is being +0.75 or less at age 6-7.(2) There’s only a little room for emmetropization and its related axial elongation in these kids before they tip over into myopia. I explain to parents that this may not require management now, but is a red flag and indicates that if their child’s eyes grow at the same rate as other children their age, they’re likely to become myopic by the time other children are becoming emmetropes / mild hyperopes at age 10-12. This doesn’t mean I haven’t seen the +0.25 6 year old surprisingly remain +0.25 for a few years, but they’re the lucky ones! Review these children at least every 12 months and more often if you’re concerned about their visual habits (bookworm / digital device addict / not outdoorsy) or binocular vision (see measuring accommodative lag and esophoria at near, below).
3. Talk about outdoor time. At least 90 minutes of outdoor time average per day reduces risk of myopia in pre-teens.(3) Extrapolation to younger groups isn’t necessarily evidence based at this stage, but it certainly can’t hurt to get more kids off their iPads and outside playing with the dog. Ask about outdoor time in your case history and discuss again in management depending on your findings and index of myopic concern.
4. Use the opportunity to discourage digital device addiction. Parents will love you for this! They need your help! While the causal link between near work and myopia development is contested, there is a definite link between the combination of high near work and low outdoor time and myopia development. You can also talk about reading distance, which should be no less than the elbow-to-hand distance when the child puts their hand next to their eye. Ideally less than 2 hours per day of non-school time should be spent on close vision tasks, which is achievable in younger children but can be near impossible in high schoolers depending on their school work demands.
5. Discuss contact lens options right from the start. Even though the child in front of you may be many years away from being ready for contact lenses, or only a very low myope, mentioning that there are contact lens options available to control myopia helps to plant the seed. Some parents are rightly concerned about contact lens safety in children but you can reassure them that there’s no difference in long term outcomes for children fit with contact lenses as pre-teens compared with teens after 10 years of wear.(4) Moreover, if their child wore contact lenses for 10,000 years, research indicates that they would likely only suffer two events of microbial keratitis wearing daily disposables, twelve MK’s wearing soft reusable lenses, and thirteen MK’s wearing orthokeratology.(5,6) Yes, reusable and OrthoK lenses carry a greater risk but it’s still remote.
6. Measure accommodative lag. This is a key modifiable risk factor in both the at-risk pre-myope and the progressing myope. Measuring accommodative lag is simple with your retinoscope – have the child look at a near card on your retinoscope, or even at your nose, while you neutralise the reflex. No correcting calculation is required – I use +/-1.00, 1.50 and 2.00 flippers to quickly gain the reading. Greater than +1.50 at 30-40cm is a definite risk factor, along with a potential source of asthenopia. In your at-risk pre-myope – for example a six year old, +0.50 at distance, two myopic parents, bookworm and +1.50 accommodative lag – you may choose not to prescribe a correction at near if sufficient accommodative reserve and facility is present, but you might want to get him back in six months instead of twelve to keep a closer watch on him. You'll frequently find that progressing myopes get very ‘laggy’ in their stronger prescriptions. If a child needs a near add, I’ll make prescribing decisions starting with +0.50 less than the near retinoscopy result and see how this improves binocular vision function, especially any esophoria.
7. Measure esophoria at near. Esophoria and accommodative lag are our two binocular vision enemies in the myopia war. Extreme language yes – but aside from visual environment advice, it’s the only modifiable factor for the at-risk pre-myope. For the progressing myope, progressive addition spectacle lenses have only been shown useful for myopia control in eso’s with accommodative lag. Frequently the two go hand-in-hand. Measure esophoria with a Howell near card, or prism neutralisation on your near cover test. More than 1 esophoria at 30-40cm generally fits the criteria. Once you apply your add as determined above, remeasure to check you’ve knocked the eso out of the equation. Free space measurement of base-in (divergent) fusional reserves also helps you to determine a child’s ability to cope with their esophoria – Sheard’s criterion states that your phoria should be no more than 1/3 to 1/2 of your fusional reserves, which I describe to parents and kids as their ‘petrol in the tank’ as compared to their ‘posture’, which is the phoria. A prism bar is great for this, where you can easily visualise whether the child is able to fuse increasing levels of base in prism by watching for stable divergence, or flitting between the images when the child is diplopic.
8. Ensure you are 100% justified, by process of elimination, before prescribing single vision spectacles for a progressing myope. There is more than enough evidence that prescribing single vision corrections, whether spectacles or contact lenses, for progressing myopes does nothing to help with myopia retardation. So if you’re going to prescribe single vision lenses for a young myope at risk of progression, ensure that they:
- Do not have esophoria or accommodative lag, in which case they’re better to be in progressive addition lenses or bifocal lenses.
- Are not (yet) suitable for contact lenses, namely multifocal soft contact lenses or OrthoK.
- Have strict instructions for when NOT to wear their glasses. Recently I saw a R&L -1.50 myope who was 10 years old, and homeschooled. Since his schoolwork was all done on a computer, with no copying from the board, I was comfortable in prescribing him single vision distance spectacles for watching TV and going outside the house with the knowledge that he wouldn’t need, and had been expressly instructed, not to wear them for close vision tasks. I’ve also provided single vision distance spectacles as a low cost back up for kids otherwise wearing multifocal glasses or contact lenses. They know not to wear these for school or reading unless some disaster has befallen their usual correction!
- Ideally have demonstrated refractive stability in recent times.
To prescribe single vision correction for a young myope, you must be satisfied that this child has normal binocular vision, is currently unsuitable for contact lens wear and knows when and when not to wear their glasses.