EyeToolkit is a free online clinical toolkit for ophthalmologists and optometrists worldwide, offering clinically validated calculators — IOL power calculation, vision conversion, astigmatism analysis, IOP correction, myopia control, and more. All tools are free and require no registration.

Who are these ophthalmic tools for?

Primarily for ophthalmologists, optometrists, medical students, and other healthcare professionals. The tools are based on standard clinical formulas and support clinical decision-making, but do not replace a physician’s professional judgment.

Which formulas does the IOL calculator support?

It supports three internationally recognized IOL power calculation formulas — SRK-T, Hoffer Q, and Haigis — so you can choose the most appropriate formula for each patient.

Yes. All EyeToolkit tools are completely free and require no registration.

How can I contact EyeToolkit?

For feedback or collaboration, email eyetoolkit@foxmail.com.

Myopia Progression Predictor — IMI 2021 Model | EyeToolkit

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📚 User Guide

How the Model Works

Annual rate P(age) = a · e^-b·age + c integrated with Simpson 1/3 from current to target age

East-Asian: a=1.00, b=0.13, c=0.20 (fastest progression, IMI 2021)

White: a=0.80, b=0.14, c=0.15 (COMET / LAMP cohorts)

Mixed: a=0.90, b=0.135, c=0.18 (IMI 2021 default)

Input Parameters

• Current age: 3-25 years

• Current SE: spherical equivalent = sphere + ½ cylinder

• Axial length: optional, IOL Master / optical biometry (mm)

• Target age: typically 18 (ocular growth stabilizes)

• Reference population: East-Asian / White / Mixed

Risk Thresholds (IMI 2021)

• Low: projected SE > -3.00 D

• Medium: -5.00 to -3.00 D

• High: -6.00 to -5.00 D (IMI threshold)

• Very High: ≤ -6.00 D (pathologic risk)

Related Guides

Myopia Progression in Children: A Parent-Friendly Guide 6 evidence-based interventions, FAQ, red flags.
Myopia Progression Predictor: The Complete Clinical Guide IMI 2021 / Brennan 2020 model details, cohort selection.

Current age (years)

Current spherical equivalent (D)

SE = sphere + ½ cylinder

Axial length (mm) optional

IOL Master / optical biometry

Predict through age (years)

Reference population

📚 Clinical Sources

All calculations follow peer-reviewed, published formulas. The list below cites the primary literature for each model.

Brennan NA, Young TL, Metzger JS. A population-based model for the rate of myopia progression. Ophthalmology, 2020;127(10):1333-1340.
International Myopia Institute (IMI) 2021 — Clinical Management Guidelines for Myopia Progression.
Holden BA, et al. Global prevalence of myopia and high myopia and temporal trends from 2000 through 2050. Ophthalmology, 2016;123(5):1036-1042.
Chiang YAL, et al. Short-term myopia progression in children: a systematic review and meta-analysis. British Journal of Ophthalmology, 2021;105(11):1547-1553.

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⚠️ Medical Disclaimer

This tool is for educational and clinical reference only, and does NOT constitute medical advice, diagnosis, or treatment. No doctor–patient relationship is created by using this tool. Always consult a licensed ophthalmologist for clinical decisions.

Questions or corrections? Email eyetoolkit@foxmail.com