The Short Answer: Glasses Don’t Make Myopia Worse; the Wrong Prescription Is What to Worry About
“Can we hold off on glasses? Once you start wearing them you can’t take them off, and the prescription just keeps getting stronger.”
We’ve heard this at the counter more times than we can count. Sometimes it’s parents speaking for their child, sometimes it’s office workers talking about themselves. The fear is concrete, and the answer is direct: wearing glasses does not make myopia worse. What’s really worth worrying about is the wrong prescription. Too weak, and you can’t see clearly and spend the day squinting; too strong, and close-up work is a strain, your eyes feel swollen, and headaches follow.
Myth 1: Glasses Make Your Eyes Dependent, So the Prescription Keeps Getting Stronger
The word “dependent” is probably why this idea has been passed around for decades. Put on glasses and the world becomes clear; take them off and it’s blurry again, and many people read that contrast as their eyes having been spoiled. In fact, the blur you see without glasses has always been how those eyes are. It’s only after wearing glasses, once you know what clear feels like, that the contrast seems so big.
Worsening Myopia Is About Axial Length, Not About Whether You Wear Glasses
A myopic prescription mainly comes from axial length, the eyeball’s front-to-back length. When the eyeball grows too long, light comes into focus before it reaches the retina, which is why distance looks blurry. A myopia lens does something simple: it spreads the incoming light slightly so the focus moves back and lands on the retina. It changes the path the light takes, but it can’t touch the length of the eyeball; it can’t make it longer, and it can’t shrink it back. Once axial length has increased, it doesn’t get shorter again, so a myopic prescription won’t go back down on its own. That’s determined by the structure of the eye, not by the lens.
So why does axial length keep increasing? That question gets a whole article of its own: the real culprit behind children’s worsening myopia (in Chinese).
Myth 2: Wearing Glasses Less Keeps Myopia From Getting Worse
This grows out of Myth 1: if you’re worried about dependence, wear them less, and skip them whenever you can. The problem is that during those hours without glasses, axial length doesn’t grow any less. Taking your glasses off changes only one thing: whether you can see clearly during that time.
Why an Undercorrected Prescription Is a Problem
Undercorrection means wearing a prescription weaker than you actually need, or having a prescription but simply not wearing glasses. The cost falls entirely on the wearer:
- Distance is blurry; road signs, the blackboard, and the projector screen in a meeting room only come into view when you squint
- Your eyes are working hard to focus all the time, so you’re especially tired by the end of the day
- Some people get headaches or a tight neck and shoulders, especially noticeable in the evening
With children, it’s harder to spot. Elementary school kids rarely say “I can’t see clearly.” What’s more common is copying things wrong from the blackboard, sitting closer and closer to the TV, and rubbing their eyes often. With a full prescription, they don’t have to push through these burdens.
Myth 3: My Prescription Goes Up Every Time, So It Must Be the Glasses’ Fault
Every time you change glasses, the number on the slip is a bit higher than last time, and it really does look like the glasses are pushing the prescription along. Broken down, there are roughly three reasons a prescription goes up, and none of them is the glasses themselves. If you had to count one, only “the last pair was too strong” makes the number on the slip look inflated.
During the Growth Years, It’s Changing Anyway
From the Health Promotion Administration (HPA)‘s 2017 vision monitoring survey: 19.8% of first graders were myopic, 70.6% by sixth grade, and 89.3% by the third year of junior high. During these years, children are growing taller and their eyes are growing too. A slightly higher number every six months is often just the eye developing, and has nothing to do with which glasses they wore.
An Overcorrected Prescription
One kind of “stronger prescription” is stronger only on the slip. If the eyes aren’t relaxed during refraction, the measured myopia tends to come out too strong. Fit glasses to that number and the slip shows another jump, even though the eyeball itself may not actually have grown that much.
Glasses that are too strong feel like this: distance is so sharp it’s a little glaring, but close-up work is a strain; your eyes feel swollen after a long time on your phone, and headaches start in the afternoon. Many people assume new glasses just take getting used to, put up with it for two weeks, and find it’s still the same. At that point, the thing to do is go back and recheck the prescription, not keep putting up with it.
Why the Autorefractor Reading Can’t Be Used Directly
An autorefractor has you look at a picture inside the machine and produces a set of numbers within a few seconds. The catch is that your eye knows the picture is really just a few centimeters away, and it unconsciously works to focus, so the measured myopia tends to come out stronger than it actually is. Children have strong focusing ability, so the gap is usually more noticeable. The autorefractor reading is the starting point of refraction. Using it directly for glasses means taking a number measured while the eye was straining and calling it your everyday prescription.
Visual Habits Haven’t Changed
There’s one more, the most common and the easiest to overlook. The glasses are new, but life isn’t. The hours you spend each day at a desk and in front of screens stay the same, and so does the distance between your eyes and your books or phone. Those two numbers won’t change no matter which glasses you switch to.
How to Avoid the Wrong Prescription: Refraction and Re-checks
Once the glasses are cleared of blame, what’s left to look after is whether the prescription is right. What can be done on the glasses-fitting side is practical: measure the prescription accurately, then come back regularly to confirm it’s still accurate.
Refraction Should Relax Accommodation, Not Use the Autorefractor Reading Directly
A more complete refraction has several more steps after the autorefractor:
- Subjective refraction: first use fogging to relax the eyes, then add the prescription back one step at a time to find the weakest prescription that still gives clear vision
- Red-green test and binocular balance: confirm the prescription isn’t too strong and both eyes are working equally
- Trial wear: walk around wearing it and look far and near, confirming there’s no dizziness or swollen feeling before finalizing
What these steps do is subtract the part that comes from the eye straining. Once that’s fully subtracted, what you measure is your everyday prescription.
How Often to Re-check: Children Every 3–6 Months, Adults Every Year
Schoolchildren’s prescriptions change quickly, so measuring every 3–6 months is recommended; for adults, once a year. If in between you notice blurry vision, unusually tired eyes, or frequent headaches, don’t wait for the scheduled time. Come straight back to be re-measured.
If you’d like your child’s prescription recorded regularly, our Xinzhuang store (Biyang Optometry Clinic) performs refraction for children aged 6 and up every 3 to 6 months and keeps it on record. The Xinzhuang children’s myopia tracking page describes what’s actually measured at each return visit. The first refraction and glasses require an ophthalmologist to first confirm the myopia is not pseudomyopia, and refraction for those aged 15 and under is carried out under an ophthalmologist’s guidance.
No. 419-1, Zhongzheng Rd., Xinzhuang Dist., New Taipei City | +886-2-2206-6700 | LINE OA: https://lin.ee/SoWj9Ft
Visual Habits: The HPA’s 3010120
Beyond lenses, what you can do yourself is set the rhythm of how you use your eyes. The HPA’s eye-care rule 3010120: after every 30 minutes of using your eyes, rest for 10 minutes, and spend 120 minutes outdoors every day. The numbers are easy to remember; actually doing it is the hard part. When your child does homework, set a 30-minute timer, and when it goes off, have them get up and walk out to the balcony. If you’re an office worker staring at screens ten hours a day, use the gaps between meetings to look out the window, not to scroll on your phone.
Glasses Take Care of Now, Not Later
Glasses don’t push the prescription up, but where the prescription goes next isn’t something the glasses-fitting side can answer either. It involves development, eye use, and other eye conditions, and the parts that need evaluating belong to an ophthalmologist. Measuring the prescription accurately and re-checking regularly is about keeping this pair in step with the eyes you have now.
FAQ: Is My Prescription Getting Stronger?
Q: Can adult myopia keep getting worse?
It can, though for most people the change is much more gradual than during their school years. Office workers who do long hours of near work may still see small shifts in their prescription now and then; other people go years without any change. Rather than guess, get re-checked once a year. Measure it and you’ll know.
Q: My child’s prescription is increasing quickly. Should we see an ophthalmologist or an optometry clinic?
Both, for different questions. Why the prescription is changing quickly, and whether medical intervention is needed, is for an ophthalmologist to judge; medication (such as low-dose atropine) is prescribed by a physician, so please see an ophthalmologist for an evaluation. What optometry staff do is regular refraction (for those aged 15 and under, under an ophthalmologist’s guidance), recording each prescription. When you see the ophthalmologist, these records can be issued for you to take along. For which to see first at what age, the route laid out by age is in Ophthalmologist first, or glasses first?.
Q: Should I take my glasses off for close-up work?
It depends on your prescription and on comfort; there’s no one-size-fits-all answer. People with a mild prescription may see a phone or a book clearly without glasses, and taking them off can feel easier. People with a stronger prescription have to bring things very close to see them without glasses, so keeping them on is less tiring. Whether to take them off comes down to seeing clearly without tiring your eyes. For how a child should wear them, please follow the ophthalmologist’s advice.
“Can we hold off on glasses?” The fear is that glasses will make things worse, but pushing through blurry vision usually buys you nothing but squinting, leaning in closer, and tiring faster. This goes double for children: when a medical evaluation is needed, we’ll help with a referral to an ophthalmologist, and the records tracking how the prescription changes are something you can leave to us to keep, one visit at a time.
Whether to get glasses, and how strong they should be, is a question answered by measurement, not by putting up with it or guessing.