If your child has myopia, it is natural to wonder whether their treatment is making a difference. At Vision Camberwell Optometrists, we measure axial length, the distance from the front to the back of the eye, as part of their myopia assessment and ongoing reviews.
This quick, non contact scan helps us track eye growth. We interpret it alongside prescription testing and eye health checks, so you can understand what has changed and what it means for your child’s care. 1
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What does axial length tell us?
Childhood myopia usually involves the eye growing too long for its focusing power. Measuring that length gives us information about the eye’s physical growth, while the prescription tells us about its focusing needs. The two measurements answer related questions. 1
Monitoring is part of treatment, rather than a treatment itself. Myopia management combines clear vision, measures to slow progression and ongoing assessment of the eyes. 4
What happens during the measurement?
Your child looks into an instrument called an optical biometer while it measures each eye. Nothing touches the eye. The scan itself does not usually require eye drops, although other parts of a comprehensive assessment may involve drops.
We will explain each step and give your child time to settle. If a reading needs to be repeated, we can take another measurement before discussing the results.
Your child’s starting measurement
At the first myopia assessment, we record axial length alongside refraction and eye health findings. This becomes a baseline for future comparisons. If your child has been measured elsewhere, bring the previous reports, including the dates and instrument details if available.
Why prescription testing still matters
An axial length scan does not replace an eye examination. Children’s focusing activity can affect prescription measurements; cycloplegic refraction uses drops to temporarily relax focusing and help establish the refractive error accurately. Eye health assessment provides information that an axial length measurement alone cannot. 1
How we interpret changes in eye length
We will talk you through your child’s results in plain language. The useful questions are how much each eye has changed, over what period, and how that fits with their age, prescription and treatment history.
There is no single ideal number for every child
Eyes grow during childhood, including eyes that do not become myopic. Research comparing treated myopic children with models of non myopic eye growth shows why some elongation can occur even when treatment is helping. The goal is to slow excessive growth, rather than promise that a growing eye will never become longer. 3
Growth rate needs context
The 2019 IMI guidelines describe approximately 0.1 mm a year as associated with normal eye growth and 0.2–0.3 mm a year as associated with increasing myopia. These are broad reference points, not individual pass or fail thresholds; younger children generally grow faster. 2
For example, a change from 24.20 mm to 24.30 mm over six months is an increase of 0.10 mm during that period. It does not establish what will happen over the next six months, or by itself tell us whether treatment should change.
Age matched research helps put growth into perspective, but population averages cannot precisely predict an individual child’s course. 3 We use the trend to guide a conversation, not reduce your child’s care to one number.
How monitoring guides treatment
At each review, we consider the measurements together with how your child is managing their treatment. Tell us about missed doses, difficulties wearing lenses, discomfort or changes in their routine. We want a practical picture of what is happening at home.
If progression appears insufficiently controlled, we may discuss improving treatment use, changing the approach or combining suitable treatments. Decisions also consider safety, vision and your child’s circumstances. 2
This monitoring can support care involving atropine drops, myopia control spectacles, soft myopia control contact lenses or orthokeratology. For children receiving repeated low level red light therapy, axial length is only one part of follow up and does not replace the treatment’s specific safety assessments.
Why it is particularly useful with OrthoK
Orthokeratology changes the shape of the cornea to correct vision, so the on-treatment prescription is not a straightforward measure of underlying myopia progression. IMI identifies axial length as an appropriate efficacy measure for orthokeratology. 4
Continuing, changing or stopping treatment
There is no universal age or fixed program length at which every child should stop myopia treatment. We will discuss the plan using their progression history and current findings. Monitoring remains important after treatment is reduced or stopped because progression can accelerate again. 2
Before you leave, we will explain when the next review is due and what we will reassess. If the current treatment is difficult to maintain, please contact us rather than waiting until the next scheduled visit.
Before your appointment
Bring your child’s current glasses, previous prescriptions and any axial length reports. If they use contact lenses or eye drops, bring the product details and tell us how they are being used.
Please ask us about any lens wear instructions before the visit, especially for OrthoK. You do not need to interpret the reports yourself. We can work through the results and your questions together.
Myopia monitoring at Vision Camberwell Optometrists
Axial length monitoring is part of our myopia management care at 784 Burke Road, Camberwell, in Melbourne’s inner east. We welcome families from Camberwell, Hawthorn, Balwyn, Kew, Canterbury and across Australia.
Consultations with Jue Wang are available in English and Mandarin. Call 03 9882 5666 or contact our team to arrange an assessment or discuss your child’s next review.
You can also read about our approach to myopia management before your visit.
Questions parents often ask
Does axial length measurement hurt?
The optical scan does not touch the eye and is usually comfortable. Your child looks into the instrument while readings are taken. Tell us if they are anxious so we can explain it at their pace.
Can the prescription stay stable while the eye grows?
Yes. Eye growth and prescription change do not always match directly because other optical components also influence focus. Research on childhood eye growth supports interpreting them together rather than assuming a stable prescription means no elongation. 3
How often should my child have monitoring?
The schedule depends on their age, progression, treatment and clinical findings. Some treatment checks are needed sooner than reviews of the longer term growth trend. We will give you a review plan suited to your child. 2
Does a small increase mean treatment has failed?
No. Some growth is compatible with a useful treatment response. We consider the amount of change, the time between measurements and the wider clinical picture before recommending a change. 3
Can the scan tell us exactly how well a treatment has worked?
It can help assess the response over time, but it cannot show exactly how the same child would have progressed without treatment. Clinical trial averages are useful evidence, not a guaranteed personal result. 4
Does monitoring mean we can skip the eye health check?
No. Tracking length does not replace examining the eye’s health or assessing vision. 1 If your child develops new symptoms, contact us for advice about an earlier assessment instead of waiting for a routine monitoring visit.
References
- Jones D, Chow A, Fadel D, et al. IMI—Instrumentation for Myopia Management. Investigative Ophthalmology & Visual Science. 2025;66(9):7. doi:10.1167/iovs.66.9.7.
- Gifford KL, Richdale K, Kang P, et al. IMI – Clinical Management Guidelines Report. Investigative Ophthalmology & Visual Science. 2019;60(3):M184–M203. doi:10.1167/iovs.18-25977.
- Chamberlain P, Lazon de la Jara P, Arumugam B, Bullimore MA. Axial length targets for myopia control. Ophthalmic and Physiological Optics. 2021;41(3):523–531. doi:10.1111/opo.12812.
- International Myopia Institute. IMI Myopia Correction, Myopia Control and Myopia Management: Definitions and Recommended Usage. Accessed 10 September 2026.
Reviewed by Dr Shonit Jagmohan, B.Optom (Hons), FIAOMC, IACMM, Ophthalmic Medicines Prescriber, Fellowship Chair for the International Academy of Orthokeratology and Myopia Control (Oceania). Last reviewed October 2026.
Visit us in Camberwell
T. (03) 9882 5666
E. vision@visioncamberwell.com.au
Find Us at:
784 Burke Rd, Camberwell
Victoria 3124, Australia
Opening Hours:
Monday, Tuesday and Friday. 9am – 6pm
Wednesday. 9am – 5pm
Thursday. 10.30am – 7.30pm
Saturday. CLOSED
Book your appointment with one of our friendly team members today
T: (03) 9882 5666
Serving Camberwell and the Surrounding South Eastern Suburbs
An independent practice in Camberwell since 1951, we are experts in myopia management and axial length monitoring for children. We welcome patients from Hawthorn, Deepdene, Surrey Hills, Balwyn, Kew, Canterbury, Box Hill, Glen Iris, and across greater Melbourne.
