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Axial Length Growth Chart Tool

Axial length (AL) measurement is the gold standard for tracking myopia progression in pediatric patients. Unlike refraction alone, AL provides an objective, reproducible biomarker that directly correlates with long-term myopia risk and the likelihood of pathological outcomes including retinal detachment, glaucoma, and macular degeneration.

Why Axial Length Matters More Than Refraction

Refractive error fluctuates with accommodation, time of day, and measurement technique. Axial length does not. A child measured at 24.5mm OD at one visit and 24.8mm six months later has demonstrably grown 0.3mm — a fact that cannot be obscured by measurement variability. At a typical early-school-age growth rate of 0.25–0.35mm/year (ages 6–9; rates decline to 0.05–0.12mm/year by age 14–16), even small interval changes carry clinical significance.

The Tideman et al. 2018 normative dataset (JAMA Ophthalmology, n=5,766 European children) and Sanz Diez et al. 2019 multi-ethnic dataset provide the population-level curves against which individual patients can be plotted. A child tracking at the 90th percentile for AL at age 9 has a meaningfully elevated risk of reaching the 26mm threshold — widely considered the boundary of pathological myopia — by adulthood.

How to Use an Axial Length Growth Chart in Clinical Practice

Plotting AL on a normative growth curve (analogous to a pediatric height-weight chart) transforms a raw millimeter measurement into a clinically interpretable risk signal. The workflow is straightforward:

Measure AL with a biometer (IOLMaster, Lenstar, MYAH, or Myopia Master) at each visit
Plot current AL against age-matched normative percentiles (50th, 75th, 95th)
Calculate annualized growth rate: (current AL − prior AL) / interval in months × 12
Compare observed growth rate to expected normative rate for age
Assess whether the patient is tracking above, at, or below population norms

Growth Rate Benchmarks (Tideman 2018)

Expected annual AL growth rates by age group, European norms:

Age 6–8: 0.25–0.35mm/year
Age 8–10: 0.20–0.30mm/year
Age 10–12: 0.15–0.22mm/year
Age 12–14: 0.10–0.18mm/year
Age 14–16: 0.05–0.12mm/year

Growth rates significantly above these ranges — particularly above 0.40mm/year — indicate accelerated progression and warrant treatment escalation review. Asian children typically show growth rates 15–20% higher than European norms at equivalent ages.

The 26mm Threshold

An axial length exceeding 26mm is associated with significantly elevated risk of pathological myopia complications. Projection of a child's current trajectory to this threshold provides a clinically meaningful target for treatment discussions. A patient currently at 24.5mm at age 9, growing at 0.40mm/year, projects to approximately 27.1mm by age 18 without intervention.

Try the Tool

MyopiaTracker plots axial length against Tideman 2018 (European), Sanz Diez 2019 (multi-ethnic), and He 2015 (Asian) normative curves in real time. Enter current AL, age, ethnicity, and a prior measurement to generate a growth chart, growth rate, percentile ranking, and treatment-adjusted projection — in under 30 seconds.

Try the tool for your patients

Plot axial length against normative curves, compare treatment outcomes, and generate a parent-ready report — in under 30 seconds. Free, no login required.

Start with a Sample Patient →

Note on ethnicity and normative curves: The percentile a child falls into is relative to their own ethnic cohort's normative dataset. Tideman et al. 2018 curves are derived from a European cohort; He et al. 2015 from a Chinese population. East Asian children show systematically longer axial length at equivalent ages compared to European norms — so an East Asian child at the 75th percentile within their own cohort is not directly comparable to a European child at the same percentile rank. The app selects the appropriate normative dataset by ethnicity automatically.

This page is provided for educational purposes. MyopiaTracker is a clinical decision support tool and does not constitute medical advice, diagnosis, or treatment. All efficacy values are population averages from published RCTs; individual patient outcomes vary. MiSight® is a registered trademark of The Cooper Companies, Inc. Stellest® is a registered trademark of Essilor International. MiyoSmart® is a registered trademark of Hoya Corporation.