When to prescribe spectacles for myopia control

The simple answer to when to prescribe spectacles is... probably to every young myope, in some form. Our first responsibility to our young myopic patients is to correct their vision. Hence, the logical first choice for myopia management is a treatment which corrects ametropia as well as providing myopia control – spectacle or contact lens options. While multifocal soft contact lenses and orthokeratology have been shown to have better myopia control efficacy on meta-analysis than standard spectacle lens options (progressive addition and bifocal lenses),1 it is important to be aware of the indications and evidence for spectacle lens myopia control, as this is likely the first correction we will prescribe. This is especially the case in younger children where the child (or perhaps more the parent!) is not ready for contact lenses. Spectacle lenses are also an important adjunct treatment in soft contact lens wearers – as a back up correction – and if atropine is being prescribed as a first line treatment. Here we explore an overview of spectacle prescribing for myopia management and provide links to further reading.

Single vision spectacle lenses

It is well known by now that single vision spectacle lenses provide no useful efficacy for myopia control, and in fact are used as control corrections in myopia control studies, demonstrating the ‘untreated’ progression of childhood myopia.2 When should you prescribe single vision lenses? Perhaps only when you’re quite sure that your patient’s myopia is stable, they are older or intolerant or unsuitable for other spectacle lens options – due to cost, cosmesis, binocular vision or other parental concerns. Single vision lenses should NOT be our first choice for myopia management, but sometimes they are our first prescription as a parent becomes educated on myopia, its progression and its management. It is a realistic clinical situation that sometimes a parent needs to see and understand their child’s myopia progression before committing to another option providing myopia management. If you are prescribing single vision lenses to a young, progressing myope – even if you’d like to do otherwise – the important steps are to ensure you’re fully informing parents that progression is to be expected and that you’re scheduling a review in a maximum of six months to evaluate progression and discuss options again.

Single vision lenses may be a reasonable option for a low myope who spends most of their time in a near work environment, for example a teenager who is -1.50 and is homeschooled, so doesn’t require their correction for most of the day. In a case like this it is important to caution against too much time spent un-corrected for long distance, as undercorrection of +0.75 or to 6/12 (20/40) acuity has been linked to myopia progression.3

Single vision lenses can be the first choice as a back up option for children wearing orthokeratology, where the spectacle wear will be infrequent. Similarly, a child wearing soft multifocal contact lenses for 6-7 days a week, for most of their waking hours, may be suitable for single vision back up spectacles provided their binocular vision at near tolerates the correction.

Single vision lenses should be used with caution in children undergoing atropine treatment, to ensure management of any side effects. When employing the currently recommended concentrations of 0.025% to 0.05% atropine, the side effects of mydriasis and cycloplegia appear to be minimal, with the LAMP study4 showing a loss of accommodative amplitude of only 2D and increase in pupil size of only 1mm for both concentrations. Another recent study showed compounded atropine 0.01% had a minimal effect on accommodative facility, near acuity or stereoacuity.5 It is important to note, though, that most atropine studies (and these two quoted above) have been undertaken in Chinese children, and children with blue irides could show a more significant side effect profile than children with brown irides.6 How should you manage this? Where possible, it might be ideal to prescribe a new pair of spectacles for a child on atropine treatment 2-3 weeks AFTER commencement, to evaluate for both objective side effects and subjective symptoms requiring a near add and/or photochromatic spectacle lenses. We don’t yet have a clear picture on the frequency and time course of side effects, but this approach allows for assessment of tolerance of atropine drops, as well as prescribing the best spectacle lens to ensure visual comfort. This initial ‘trial’ period also helps to confirm commitment to ongoing atropine treatment by both the parent and the patient.

Progressive and bifocal spectacle lenses

These are standard lens designs to which most primary eye care practitioners across the world will have access. Progressive addition (PAL) and bifocal spectacle lenses have shown reasonable research results for myopia control. There is some disagreement about PALs having any useful effects for myopia control.7, 8 This is likely because PAL studies for myopia control show negligible results when single adds are applied to all children, however when applied to children with esophoria and accommodative lag, the results become more impressive at 30-40% efficacy and start to approach that of contact lens studies.9, 10 By comparison, a three year bifocal study found a 40-50% efficacy for a +1.50 Add E-seg bifocal with 3 base-in (BI) prism incorporated.11 You can read more about this in our blog Spectacle lenses for myopia control: progressives, bifocals and binocular vision.

Is the bifocal a better option than a PAL? Perhaps, as the research results indicate - check out this useful review of bifocal lens control of myopia control in children, which is open access. It’s important, though, to understand why the BI prism was added. The +1.50 Add with 3 BI R&L ensured that there was no change to either lag or phoria once wearing the bifocal, essentially making the treatment mechanism about the large area of differential focus provided by the add section of the lens rather than the effect on binocular vision.12 The base-in prism ensured the exophoric children didn’t get more exophoric with the add. However you may want to change phoria and lag with a near add in a child with esophoria and accommodative lag.

The table below below provides a summary of where our standard spectacle lens designs work best based on binocular vision presentation. PALs appear to work meaningfully for children with esophoria and accommodative lag.9, 10 Cheng et al’s three year bifocal study found a moderate myopia control effect in children who were orthophoric and exophoric in their baseline single vision correction. The authors found a minimal effect in the baseline esophoric children, after two years of wear, but they were a small group so there was less statistical power.11 In the three year study, phoria didn’t influence efficacy, hence the table below shows a tentative approval for bifocal efficacy in esophores. When analysed by accommodative lag, the three year results showed the similar effect of both bifocal types in children with high accommodative lag (over 1D), but a better result with the prismatic bifocals in children with low accommodative lag.13

OA_1 Figure 1 standard specs

If you’d like to read more on binocular vision, you can start with Four reasons why binocular vision matters in myopia management, and then head to our Expand my Clinical Skills portal of the website for loads more resources to upskill in BV. We also have our popular Binocular Vision Fundamentals online course available to help you take the next steps in understanding and applying BV in practice. This course is useful for management of myopic and non-myopic patients, and in fact any of your patients who have two functioning eyes (which is hopefully most of them)!

Myopia control specific spectacle designs

The next phase sees novel spectacle lens designs becoming available which appear to work as well as our contact lens options. The first-to-market of these is the Defocus Incorporated Multiple Segments (DIMS) spectacle lens, developed at Hong Kong Polytechnic University, which has been commercialized by Hoya and released in Asia in 2019. The DIMS lens has a 10mm clear central optical zone with the distance correction, and then is covered with +3.50 lenslets with regions of the distance correction in between the lenslets. The intended result is that wherever a child looks in the lens, they’ll experience 50% of retinal focus being their distance correction, and 50% of the +3.50 Add – the concept of simultaneous defocus. The DIMS lens looks like a single vision lens but could work more like a contact lens because of its innovative design, and has shown contact-lens-level results of 50% refractive control and 60% axial length control in the newly published two year study.14

Additional research into novel lens designs are underway – read more in our blog Spectacle Lenses for Myopia Control: New Designs and Latest Studies.

To fully or under-correct?

The answer – fully correct! Nicola Logan and James Wolffsohn conducted a systemic review on the evidence around under-correction, over-correction and no correction when treating myopia and the resultant rate of myopic change. With some contradictory results and variable study quality, under-correction definitely didn't appear to benefit and in some studies increased myopia progression. Unfortunately, under-correction is still regularly practiced as a myopia control strategy across the world, by both primary eye care providers and ophthalmologists.

The overall findings were that "there is no strong evidence of benefits from un-correction, monovision or over-correction. Hence, current clinical advice advocates for the full-correction of myopia. Further studies are warranted to determine the level of myopia that can be left uncorrected without impacting on myopia progression and how this changes with time."15

In reality, we can never perfectly control for under-correction, regardless of the spectacle lens type we choose to prescribe - our young progressing myopes are likely spending some percentage of their time between appointments under-corrected, despite our best efforts. Wearing time can also influence a child's experience of full-, under- or no correction between appointments. Ensuring compliance with wearing time and with regular clinical review is important.

Further reading on spectacle lenses for myopia control

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About Kate

Dr Kate Gifford is a clinical optometrist, researcher, peer educator and professional leader from Brisbane, Australia, and a co-founder of Myopia Profile.

References

  1. Huang J, Wen D, Wang Q, McAlinden C, Flitcroft I, Chen H, Saw SM, Chen H, Bao F, Zhao Y, Hu L, Li X, Gao R, Lu W, Du Y, Jinag Z, Yu A, Lian H, Jiang Q, Yu Y, Qu J. Efficacy Comparison of 16 Interventions for Myopia Control in Children: A Network Meta-analysis. Ophthalmol. 2016;123(4):697-708. (link)
  2. Donovan L, Sankaridurg P, Ho A, Naduvilath T, Smith ELI, Holden BA. Myopia progression rates in urban children wearing single-vision spectacles. Optom Vis Sci. 2012;89:27-32. (link)
  3. Chung K, Mohidin N, O'Leary DJ. Undercorrection of myopia enhances rather than inhibits myopia progression. Vision Res. 2002;42(22):2555-2559. (link)
  4. Yam JC, Jiang Y, Tang SM, Law AKP, Chan JJ, Wong E, Ko ST, Young AL, Tham CC, Chen LJ, Pang CP. Low-Concentration Atropine for Myopia Progression (LAMP) Study: A Randomized, Double-Blinded, Placebo-Controlled Trial of 0.05%, 0.025%, and 0.01% Atropine Eye Drops in Myopia Control. Ophthalmol. 2019;126:113-124. (link)
  5. Wang Y, Yao J, Qu X. Atropine 0.01% for the Control of Myopia in Chinese Children: Effect on Accommodation Functions and Pupil Size. J Ophthalmol. 2020;7525180. (link)
  6. Obianwu HO, Rand MJ. The relationship between the mydriatic action of ephedrine and the colour of the iris. BR J Ophthalmol. 1965;49(5):264-270. (link)
  7. Cheng D, Woo GC, Schmid KL. Bifocal lens control of myopic progression in children. Clin Exp Optom. 2011;94(1):24-32. (link)
  8. Berntsen DA, Sinnott LT, Mutti DO, Zadnik K. A randomized trial using progressive addition lenses to evaluate theories of myopia progression in children with a high lag of accommodation. Invest Ophthalmol Vis Sci. 2012;53(2):640-649. (link)
  9. Gwiazda J, Hyman L, Hussein M, Everett D, Norton TT, Kurtz D, Leske MC, Manny R, Marsh-Tootle W, Scheiman M. A randomized clinical trial of progressive addition lenses versus single vision lenses on the progression of myopia in children. Invest Ophthalmol Vis Sci. 2003;44:1492-1500. (link)
  10. Yang Z, Lan W, Ge J, Liu W, Chen X, Chen L, Yu M. The effectiveness of progressive addition lenses on the progression of myopia in Chinese children. Ophthalmic Physiol Opt. 2009;29:41-48. (link)
  11. Cheng D, Woo GC, Drobe B, Schmid KL. Effect of bifocal and prismatic bifocal spectacles on myopia progression in children: three-year results of a randomized clinical trial. JAMA Ophthalmol. 2014;132(3):258-264. (link)
  12. Cheng D, Schmid KL, Woo GC. The effect of positive-lens addition and base-in prism on accommodation accuracy and near horizontal phoria in Chinese myopic children. Ophthalmic Physiol Opt. 2008;28(3):225-237. (link)
  13. Cheng D, Schmid KL, Woo GC, Drobe B. Randomized Trial of Effect of Bifocal and Prismatic Bifocal Spectacles on Myopic Progression: Two-Year Results. Arch Ophthalmol. 2010;128:12-19. (link)
  14. Lam CSY, Tang WC, Tse DY, Lee RPK, Chun RKM, Hasegawa K, Qi H, Hatanaka T, To CH. Defocus Incorporated Multiple Segments (DIMS) spectacle lenses slow myopia progression: a 2-year randomised clinical trial. Br J Ophthalmol. 2020;104:363-368. (link)
  15. Logan NS, Wolffsohn JS. Role of un-correction, under-correction and over-correction of myopia as a strategy for slowing myopic progression. Clin Exp Optom. 2020;103(2):133-137. (link)

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