When to prescribe spectacles for myopia control

Originally posted July 14, 2020
Updated July 3, 2023

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.

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.

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 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

If you'd like to read more on binocular vision, you can start with Four reasons why binocular vision matters in myopia management, and there are numerous further articles on the website to help you 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)!

New spectacle lens technology for myopia control allows for spectacle correction of myopia that is on par with the best contact lens options in terms of efficacy. These myopia controlling lens are essentially like single vision lenses with an overlying treatment zone incorporated; they do not influence binocular vision, and are easy to fit. The overlying treatment zone differs depending on the lens design you choose. These lens designs include:

• The DIMS Technology spectacle lens: these feature a honeycomb-shaped array of lenslets, each just over 1mm in diameter. Every lenslet provides a +3.50D relative myopic defocus (an 'add', but not in the orthoptic sense) and there are spaces between each lenslet where the single-vision correction is accessible to the wearer.¹⁴

• The H.A.L.T. Technology spectacle lens: these feature a concentric array of 11 rings of lenslets. Within a ring are lenslets of the same power which are touching (contiguous), but each ring is of a different power. The lenslets are just over 1mm in diameter, and are aspheric rather than being a single focal power. There are spaces between the rings where the single-vision correction is accessible to the wearer.¹⁵

• The DOT 0.2 spectacle lens: these lenses do not use lenslets. Instead, they are designed to reduce contrast signalling in the retina to slow myopia progression, providing clear central vision with a slightly less contrast in the 'peripheral' component of the lens. The clear central portion is useful for fine detail and aids the practitioner to measure the lens power.¹⁶

The purpose of the treatment zone is to create a differential myopia defocus across the retina. The DIMS and H.A.L.T. lenses are based on the simultaneous defocus theory of myopia,^14-15 whereas the DOT lenses are based on the contrast theory.¹⁶ At this stage, these new generation of myopia controlling spectacle lenses can be considered broadly similar in terms of their efficacy: slowing axial elongation by around 50% (around half).^14-16

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."¹⁷

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.

If a parent is rejecting any myopia correction for their child, this can present a significant challenge before even thinking about discussing myopia control. For help on this, read this clinical case study - Communicating with parents who reject myopia correction.

• Progressives, bifocals and binocular vision

• Back ups and dispensing considerations

• New designs and latest research

• Communicating with parents who reject myopia correction