Data
Average Axial Growth Rate by Age — the Reference Numbers
How fast is a child's eye supposed to grow? These are the working reference values behind the 6S tracker's warning logic.
The reference table
| Age (years) | Physiological growth, boys (mm/yr) | Physiological growth, girls (mm/yr) | On treatment — good target | Fast-growth flag |
|---|---|---|---|---|
| 6–7 | 0.15 – 0.17 | 0.15 – 0.16 | ≤ 0.20 | > 0.30 |
| 8–9 | 0.10 – 0.13 | 0.10 – 0.13 | ≤ 0.20 | > 0.30 |
| 10–11 | 0.07 – 0.10 | 0.06 – 0.09 | ≤ 0.15 | > 0.25 |
| 12–13 | 0.05 – 0.07 | 0.04 – 0.06 | ≤ 0.10 | > 0.20 |
| 14–16 | 0.02 – 0.04 | 0.02 – 0.03 | ≤ 0.05 | > 0.15 |
Physiological values are rounded from pooled emmetropic-eye models of large multi-cohort datasets (East Asian and European children; boys' eyes run slightly longer and grow about 7% faster). The "good target" and "fast-growth flag" columns are clinical working rules, not diagnosis thresholds — always interpret with your eye-care professional.
How to use this table
Never grade a single measurement
A 7-year-old at 23.2 mm can be perfectly normal (tall kid, flat cornea). Compute the rate: (today − last time) ÷ years between. Two measurements at the same clinic, same device, at least 3 months apart.
Compare the rate to the age band
Below the physiological band: on track. Persistently above it: the eye is outpacing childhood. For a child already on myopia-control treatment, the "good target" column is what success looks like — slowing to near-physiological speed is a win, even if growth doesn't reach zero.
Expect the deceleration
Growth naturally slows with age — a flat curve at 15 means something different than a flat curve at 8. Judge a treatment only against what the eye would have done at that age. This is why the tracker anchors your child's curve to age-based percentiles instead of a single "normal" line.
Where these numbers come from
The physiological bands synthesize published models of emmetropic eye growth — including the classic longitudinal datasets (e.g., Zadnik and colleagues, where non-myopic children's eyes grew from about 22.6 to 23.3 mm between ages 6 and 14 while staying emmetropic) and recent large pooled analyses spanning tens of thousands of children, which found growth declining non-linearly from ~0.17 to ~0.03 mm/year between ages 6 and 16, with small sex and ethnic differences. This page is an educational reference, continuously updated as new normative data publishes.
Interactive
Where does your child's lane end at 18?
One measurement per eye is enough to start. Enter your child's age and the latest axial length for each eye (from any biometry report — plus the measured refraction, if the report has it), pick the reference population that matches your child — the CREAM consortium's European/Australian database (sex-specific curves, ages 6–18) or the Chinese reference (sex-combined, ages 3–18) — and we pinpoint each eye's exact percentile lane, project it to age 18 (axial length and estimated refraction), and grade the risk. Same report format as the 6S tracker: this page does the first-measurement estimate; the tracker does the long-term management.
CREAM curves are sex-specific.
Axial length — percentile lanes and projection to 18
Refraction projection to 18 — starts from your measured value if entered, else the axial-length rule of thumb
Reference data, two options: (1) sex-specific axial-length percentiles for European/Australian children aged 6–21, from the CREAM (Consortium for Refractive Error and Myopia) population database; (2) sex-combined percentile curves for Chinese children aged 3–18. Chinese eyes run longer on average — pick the population your child belongs to for the most meaningful lane. Method note: the projection assumes the eye holds its current percentile lane to age 18 — a simplification used for orientation, not a clinical prediction. The refraction estimate applies the rule of thumb of −2.5 to −3.0 D per mm beyond a 24 mm emmetropic baseline; actual refraction depends on corneal and lens power, which axial length alone cannot see; growth spurts and interventions also move the outcome. If you also enter the measured refraction from the same visit, the refraction projection starts from that number instead of the axial-length-only estimate. Axial length around 26 mm and beyond is the range where high-myopia complications climb steeply. Educational tool, not medical advice.
Standalone version, easy to bookmark and share: 6smyopia.com/tools/axial-length-projector.html — same tool, nothing else on the page.
Plot your child against these bands.
The free 6S tracker does the rate math and the percentile anchoring for you.
Evidence base for this page (axial growth reference values): #3 · #26 · #34 — full citations and DOI links in our Evidence Library.