Short-sightedness

How fast is too fast? Yearly myopia change by age

There is no official line for 'too fast', but the studies give parents a ruler. Typical yearly change on ordinary glasses, how age shifts it, and when it is time to ask about slowing it.

by Dr Chan Li Yen · MBBS, MOphth (UM), Fellowship in Paediatric Ophthalmology & Strabismus

Dr Chan Li Yen, consultant paediatric ophthalmologist, MMC 43128, NSR 132980 · Eagle Eye Centre Kuala Lumpur, Petaling Jaya

11 min read · 2,063 words

Key takeaways

On ordinary single-vision glasses, a meta-analysis of 20 studies found about 0.55 dioptres of change in a year in children of mainly European descent and 0.82 in Asian children, at a mean age of 9.3. The International Myopia Institute puts it at about 0.50 to 1.00 D a year.
Younger children usually change faster. The guideline says progression is most rapid at about 7 to 12 and slows through the teens.
There is no official cut-off for fast. Singapore researchers called under 0.50 D a year slow and over 1.25 D a year fast, and the first year's change predicted the next two better than age or starting prescription.
Earlier onset matters. In a Guangzhou cohort, 53.9 percent of those who became short-sighted at 7 or 8 had high myopia as adults, against 1.3 percent when it began at 12 or older.
Ask an eye doctor about slowing it when the change is above about 0.50 D a year, when it started early, or when you are worried. Cochrane rates the certainty for several treatments as low or very low.

You open the new prescription and the number has gone up again. Many parents of a short-sighted child (rabun jauh) ask the same thing: is this normal, or is it too fast? Nobody has an official line that says "this much is fine, that much is too much", but the studies do give us a ruler.

This article sets out what the ruler looks like, how age changes it, and when it makes sense to ask an eye doctor about slowing things down. It is a way to read your child's numbers, not a test you can run at home.

How much does a child's short-sightedness normally change in a year?

On ordinary single-vision glasses, a child of about nine typically changes by roughly half to just under one dioptre a year. A dioptre (written D) is the unit of lens strength, so a change of 0.50 D is one step on the prescription slip.

The best-known figure comes from a 2012 meta-analysis of 20 studies of children wearing single-vision glasses, all measured with drops that relax the eye's focusing (cycloplegic drops) for an accurate reading. After one year at a mean age of 9.3, the change was 0.55 D in groups of mainly European descent and 0.82 D in Asian groups. The International Myopia Institute guideline, written by an international panel of eye specialists, summarises it as about 0.50 to 1.00 D a year, depending on age and sex. In the same analysis, girls changed slightly faster than boys at an average age of 8.8 (0.80 D against 0.71 D a year).

The 2025 Cochrane review of myopia control trials points the same way. Children in the untreated groups changed by a median of 0.65 D in the first year and 1.01 D over two years. These are averages. Your child may sit above or below them for good reasons that have nothing to do with anything you did.

Does the ruler change with age?

Yes. The younger the child, the faster the change tends to be. The International Myopia Institute guideline says short-sightedness generally progresses most rapidly in the pre-teen years, about 7 to 12, and slows through adolescence and into adulthood.

One analysis puts a number on it. In 187 children aged 5 to under 13, followed for 30 months, each year younger at the start went with about 0.19 D more change, and about 0.13 mm more growth in the length of the eyeball. That was a post hoc look at trial data (a look back at data gathered for another purpose), so it describes a pattern in a group, not a rule for one child.

The eye is still growing, and that is the reason. Short-sightedness usually means the eyeball has grown too long from front to back. Once growth slows, the number settles, which is the subject of when short-sightedness stops getting worse.

Malaysian figures show the same climb with age. A 2026 review of 14 Malaysian studies covering 13,367 children found myopia in 2.54 percent of children aged 0 to 6, 26.48 percent of those aged 7 to 12, and 42.71 percent of adolescents aged 13 to 18. A Klang Valley school screening of 459 children aged 6 to 12, reported in The Star in August 2025, put the peak at age 9, at 44.7 percent. These are group figures from different methods, and not a forecast for your child.

What counts as fast?

There is no official cut-off. Researchers have used less than 0.50 D a year as slow and more than 1.25 D a year as fast, and the International Myopia Institute guideline treats a past change above 0.50 D a year as a sign of faster change to come.

In the Singapore Cohort Study of the Risk Factors for Myopia, researchers followed 618 short-sighted children aged 7 to 9. Those who changed by less than 0.50 D in the first year changed by 0.41 D a year over the next two. Those who changed by more than 1.25 D in the first year went on to change by 0.82 D a year. The first year's change predicted the next two better than the starting prescription, age at onset or age alone.

The eye's length is a second ruler. The guideline says healthy eye growth is about 0.1 mm a year, and that 0.2 to 0.3 mm a year goes with increasing short-sightedness. It adds that individual children can progress with smaller changes, so the length is a clue, not a verdict. The guideline also notes that progression can be greater in winter than summer, so one 6-month interval can mislead.

Read all of this loosely. These are the lines researchers drew, not a diagnosis. A child who is at 0.45 D one year and 0.60 D the next has not crossed a cliff edge, and it is the pattern over several visits that counts.

Why does the age short-sightedness starts matter so much?

Because an earlier start means more growing years ahead, and the number that results tends to be higher. A Chinese twin study followed children into adulthood, mostly with annual cycloplegic eye tests, and the share who ended up with high myopia (-6.00 D or worse) fell sharply for each year later that myopia began.

In that Guangzhou cohort of 443 children who became short-sighted, 53.9 percent of those whose myopia began at 7 or 8 had high myopia as adults, against 32.4 percent at age 9, 19.4 percent at 10, 14.1 percent at 11 and 1.3 percent at 12 or older. The numbers are from one Chinese cohort of modest size, so Malaysian children may differ, but the direction is consistent with the guideline. High myopia is the reason doctors care about speed, because it raises the lifetime risk of retinal and other eye problems, as explained in high myopia: what changes once the number gets high.

It also explains why an early check is a sound idea. A child who is only just short-sighted at seven or eight is the one to watch, and the stage before it is covered in pre-myopia, at risk but not short-sighted yet.

When should I ask an eye doctor about slowing it down?

When the change is above roughly 0.50 D a year, when it started early, or when you are simply worried. There is no wrong time to ask, and the question is not "do we treat" but "what is my child's pattern, and what are the options".

Bring the last two or three prescriptions with their dates. Ask whether they were measured the same way, with or without drops, because numbers taken by different methods may not be comparable. The guideline asks for a consistent method at every visit.

Ask too what the evidence is for each option, and how sure it is. The 2025 Cochrane review, covering 104 trials and 17,509 children, found that several treatments may slow change, but rated the certainty low or very low for low-dose atropine, defocus spectacle lenses and multifocal soft contact lenses, and said there was less evidence beyond two years. The guideline also notes that no published trial has tested the best age or prescription at which to begin. That is why it is a judgement for you and an eye doctor together, based on your child's own measurements. Our article on drops, lenses and the honest numbers sets out the options, and if you receive a quote, the checklist in before you pay for myopia control helps you weigh it.

Outdoor time is free and worth starting now whatever the number, and two hours outside explains what it can do.

How can I keep track of my child's change without overreading it?

Keep each prescription with its date, how it was measured and the eye doctor's or optometrist's note, and look at the trend across visits, not one jump. A slip showing a larger number does not by itself say the child is progressing fast.

The American Academy of Ophthalmology says short-sightedness is often found between ages 8 and 12, can worsen through the teens, and between 20 and 40 usually changes little. A regular check, with the same method each time, is the dependable way to see which line your child is on. If the glasses seem weaker within a few months, or your child starts sitting closer to the board again, do not wait for the next scheduled visit.

See an eye doctor sooner if…

The glasses seem weaker within a few months, or your child sits closer to the board or screen again.
The last prescription changed by more than 1.25 dioptres in a year, the level one Singapore study called fast.
Vision suddenly worsens, or one eye is clearly worse than the other.
Your child squints, rubs the eyes or gets headaches after reading for a short time.
Your child sees flashes of light, a shower of new floaters or a curtain over part of the vision: same-day care.

Common questions

How much should my child's myopia increase each year?

On ordinary glasses, typically about 0.50 to 1.00 dioptres a year around age 9, depending on age, sex and ethnicity. A 2012 meta-analysis of 20 studies found 0.55 D in children of mainly European descent and 0.82 D in Asian children after one year. These are averages, and your child's own pattern across several visits matters more.

Why is my child's myopia getting worse so fast?

Usually because the eye is still growing, and younger children grow and change faster. The International Myopia Institute guideline says progression is most rapid at about 7 to 12. An earlier start, a higher starting number and a faster previous year are all linked with faster change ahead. An eye doctor can measure it properly and explain what applies to your child.

What counts as fast myopia progression?

There is no official cut-off. Singapore researchers called under 0.50 D a year slow and over 1.25 D a year fast in 618 children aged 7 to 9. The International Myopia Institute guideline treats a past change above 0.50 D a year as a sign of faster change to come. Treat these as research lines, not a diagnosis.

Does the age myopia starts change how high it will go?

Yes, on average. In a Guangzhou cohort of 443 children who became short-sighted, 53.9 percent of those with onset at 7 or 8 had high myopia (-6.00 D or worse) as adults, against 32.4 percent at age 9, 19.4 percent at 10, 14.1 percent at 11 and 1.3 percent at 12 or older. It is one cohort, and it describes groups, not one child.

How is axial length different from the number on the glasses?

Axial length is the front-to-back length of the eyeball, measured with a quick scan, and the glasses number measures focusing power. The guideline puts healthy eye growth at about 0.1 mm a year and 0.2 to 0.3 mm a year with increasing myopia. It is a useful clue, not a verdict, and not every clinic has the instrument.

When should I ask an eye doctor about slowing myopia?

When the change is above about 0.50 D a year, when it began early, or whenever you are worried. Bring the last two or three prescriptions with their dates and ask how they were measured. Cochrane's 2025 review found several treatments may slow change but rated the certainty low or very low for several, so it is a judgement made together.

Can I measure my child's myopia progression at home?

No. Only a proper eye examination, ideally with the same method each time, gives numbers you can compare. At home you can keep each prescription with its date and method and look at the trend, and watch for a child sitting closer to the board or screen, squinting or getting headaches.

References

Optometry and Vision Science · Myopia progression rates in urban children wearing single-vision spectacles (2012) · pubmed.ncbi.nlm.nih.gov
Investigative Ophthalmology & Visual Science · IMI Clinical Management Guidelines Report (2019) · pubmed.ncbi.nlm.nih.gov
Translational Vision Science & Technology · Annual Myopia Progression and Subsequent 2-Year Myopia Progression in Singaporean Children (2020) · pubmed.ncbi.nlm.nih.gov
JAMA Ophthalmology · Association of Age at Myopia Onset With Risk of High Myopia in Adulthood in a 12-Year Follow-up of a Chinese Cohort (2020) · pubmed.ncbi.nlm.nih.gov
Optometry and Vision Science · Baseline factors associated with myopia progression and axial elongation over 30 months in children 5 to 12 years of age (2024) · pubmed.ncbi.nlm.nih.gov
Cochrane · Interventions for myopia control in children: a living systematic review and network meta-analysis (2025) · pubmed.ncbi.nlm.nih.gov
Malaysian Journal of Medical Sciences · Prevalence of Myopia in Children and Adolescents: A Systematic Review of Malaysian Prevalence Studies (2026) · pubmed.ncbi.nlm.nih.gov
The Star · Too many kids with eye problems (26 August 2025) · www.thestar.com.my
American Academy of Ophthalmology · Myopia (nearsightedness) · www.aao.org

By Dr Chan Li Yen. General information only. It does not replace a consultation. If you are worried about your child's eyes or vision, please see an eye doctor.