Is 1 Diopter Per Year Myopia Progression Fast?
Yes — progression of 1.00 diopter per year is considered fast, especially in children under age 12. Axial length growth above 0.30 mm/year is a clinical concern.
Calculate your child's progression →Is Myopia Getting Worse Too Fast?
Normal vs Dangerous Progression Rates
Short answer: It depends on age. A 7-year-old growing 0.30mm/year of axial length is average. A 14-year-old growing the same rate is fast. The number that matters most is axial length change per year — not the diopter change on a glasses prescription.
Why age matters for interpreting progression
Eye growth naturally decelerates with age. The same axial length growth rate that is completely normal at age 7 is alarming at age 14. This is why comparing progression rates without age context is meaningless.
| Age | Average AL growth/year | Fast (>threshold) | Clinical category |
|---|---|---|---|
| 6–8 years | 0.25–0.35 mm/yr | >0.40 mm/yr | Treatment strongly recommended if fast |
| 8–10 years | 0.20–0.30 mm/yr | >0.35 mm/yr | Treatment recommended if fast |
| 10–12 years | 0.15–0.25 mm/yr | >0.30 mm/yr | Treatment recommended if fast |
| 12–14 years | 0.10–0.18 mm/yr | >0.25 mm/yr | Treatment recommended if fast |
| 14–16 years | 0.05–0.12 mm/yr | >0.18 mm/yr | Review; most progression slowing naturally |
| 16–18 years | 0.03–0.08 mm/yr | >0.12 mm/yr | Usually approaching stabilisation |
Based on Tideman JWL et al. Acta Ophthalmologica 2018;96(3):301–309. Normative values are for European/white children; East Asian children may show higher average rates. Individual variation is substantial.
Diopter changes vs axial length changes
Most parents track myopia progression by prescription change (diopters) — but this has limitations. The diopter number depends on both axial length and corneal curvature, so the same diopter change can represent different amounts of actual eye growth depending on the eye's geometry.
Axial length in millimetres, measured with optical biometry, is the more direct and reliable measure of myopia progression. If your optometrist measures axial length at every visit, this is best practice — ask for it to be recorded.
Is going from −2 to −5 in two years dangerous?
Yes — that rate (approximately −1.50D per year) is more than double the threshold for fast progression. At this rate, a child who starts at −2D at age 9 would reach −11D by age 18 without any intervention. This is significantly beyond the 26mm threshold where serious structural complications begin.
A child in this situation needs a myopia management intervention, not a new pair of glasses. The two are not the same thing.
When does myopia naturally stop progressing?
In most people, axial length growth decelerates through the mid-teens and stabilises in the late teens to early 20s. However, this varies: some people continue progressing into their mid-20s, and a small fraction (particularly high myopes) continue throughout adulthood at a slower rate.
The risk of fast progression is highest between ages 8 and 14 — the window when treatment has the most cumulative benefit.
Calculate your child's exact progression rate
Enter age, current axial length, and prior axial length to calculate mm/year growth rate and compare to age-matched norms.
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This page is for educational purposes and does not constitute medical advice. MyopiaTracker is a decision-support tool — not a diagnostic device. MiSight® is a registered trademark of The Cooper Companies. Stellest® is a registered trademark of Essilor International. MiyoSmart® is a registered trademark of Hoya Corporation. Treatment availability and regulatory approval vary by country. Consult a qualified optometrist or ophthalmologist for personalised advice.