Is -8.00 Myopia Bad?

Short answer: −8.00D is very high myopia. At this level, axial length is typically 27–28mm — substantially above the structural risk threshold. Serious complications are not inevitable, but the lifetime risk is significantly higher than for moderate myopia. Specialist monitoring is essential.

Very High myopia · Approx. axial length: ~27.0–28.0mm

Where -8.00 sits in the risk spectrum

Myopia severity is better understood through axial length (the physical length of the eye in millimetres) than through the diopter number alone. Two people can have the same prescription from different amounts of axial elongation — and axial length is what determines long-term structural risk, not the diopter number itself.

PrescriptionApprox. axial lengthStructural risk category
-1.00D~24.2mmLow
-2.00D~24.7mmLow–Moderate
-3.00D~25.2mmModerate
-4.00D~25.8mmModerate–High
-5.00D~26.1mmHigh
-6.00D~26.6mmHigh (IMI threshold)
-8.00D~27.5mmVery High
-10.00D~29.0mmExtreme

AL–refraction mapping is approximate (±2–3D individual variation). Based on Flitcroft 2012; Tideman et al. 2016. Your row is highlighted.

Clinical perspective

At −8.00D, axial length is approximately 27.0–28.0mm. Eyes at this length have substantially elevated risk of myopic maculopathy, retinal detachment, posterior staphyloma, and myopia-related glaucoma. Myopic maculopathy is a leading cause of legal blindness in many East Asian countries, predominantly affecting this range. Regular OCT imaging of the macula and peripheral retinal examination are essential components of care.

For parents: what this means for a child at -8.00

A young person at −8.00D has already reached a level that warrants concern. The priority is stopping further progression and establishing a retinal surveillance programme. Annual ophthalmic review minimum; twice yearly is better.

The number that matters most is not the prescription — it's the rate of change. A child going from -8.00 to -8.75D in one year is progressing faster than a child going from -7.50D to -8.00 over two years. Enter two measurements in MyopiaTracker to calculate the actual progression rate.

What to do at -8.00

If any progression remains at −8.00D, maximum-efficacy management (combination therapy, ophthalmology referral). For adults: specialist retinal monitoring; low vision services if needed. Avoid high-impact contact sports that risk retinal detachment.

Calculate your exact progression rate

Enter age and two axial length measurements. Get progression rate, AL percentile, and projected prescription at age 18 — with and without treatment.

Check progression now →
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Sources: Tideman JWL et al. JAMA Ophthalmol. 2016;134(12):1355–1363 (axial length risk) · Flitcroft DI. Prog Retin Eye Res. 2012;31(6):622–660 (AL–refraction modelling) · IMI 2025 Digest · Holden BA et al. Ophthalmology. 2016 (global prevalence)

This page is for educational purposes and does not constitute medical advice. Diopter-to-axial-length conversions are approximations (±2–3D individual variation). MyopiaTracker is a decision-support tool — not a diagnostic device. Consult a qualified optometrist or ophthalmologist for personalised advice.