You've had your glasses for a couple of years, they seem to be doing their job, and then your latest eye test reveals that your prescription has changed. Why?
If you've ever wondered why your eyesight seems to be getting worse or why you suddenly need stronger glasses, you're certainly not alone.
Changes to your glasses prescription are common. Our eyes change throughout our lives, and there are several reasons why your vision might not be quite what it used to be. While some changes are a natural part of getting older, others are worth investigating.
Here's what could be behind your changing prescription, when to book an eye test and why stronger glasses aren't necessarily something to worry about.
Why does my glasses prescription change?
Your glasses prescription reflects how your eyes focus light to produce clear vision. When that focusing changes, your prescription may need to change too.
There isn't one single reason for this. Your age, the shape of your eyes, your eye health and even certain aspects of your daily routine can all play a part.
1. Your eyes naturally change with age
Just as the rest of our bodies change over time, so do our eyes.
One of the most common age-related changes is presbyopia, which usually becomes noticeable in your 40s. As the natural lens inside your eye gradually becomes less flexible, focusing on close-up objects becomes more difficult.
You might notice yourself holding your phone further away, struggling to read small print or needing brighter lighting when reading.
This doesn't necessarily mean your distance vision is getting worse. You may simply need additional help with close-up tasks, such as reading glasses or varifocals.
2. Your short-sightedness or long-sightedness has changed
If you're short-sighted (myopic), distant objects appear blurry. If you're long-sighted (hyperopic), you may have difficulty focusing on nearby objects, although this varies with age and the strength of your prescription.
Both conditions can change over time.
Short-sightedness commonly develops and progresses during childhood and adolescence, although changes can continue into adulthood. Long-sightedness can also become more noticeable as your eyes' natural focusing ability changes with age.
If road signs seem less clear than they used to, or you're finding it harder to focus on your laptop, it could be time to have your prescription checked.
3. Your astigmatism has changed
Astigmatism is another common reason your glasses prescription might change.
It occurs when the cornea or lens has a shape that causes light to focus unevenly, resulting in blurred or distorted vision at different distances.
Astigmatism can change over time, meaning your glasses may need adjusting even if your short-sightedness or long-sightedness hasn't changed significantly.
4. Changes in your eye health
Not every change in vision is simply a matter of needing stronger glasses.
Certain eye conditions, including cataracts, can affect how clearly you see and may alter your prescription. Other conditions can cause changes in vision that glasses alone cannot correct.
This is one of the reasons regular eye examinations are so important. Your optometrist doesn't just check which lenses help you see clearly; they also assess your overall eye health and look for signs that may require further investigation.
Can screen time change your glasses prescription?
If you spend most of your working day looking at a computer, you've probably wondered whether all that screen time is making your eyesight worse.
Prolonged screen use can contribute to digital eye strain, which may leave your eyes feeling tired, dry or temporarily blurry. We also tend to blink less when concentrating on screens, which can make these symptoms more noticeable.
However, temporary blurriness from screen use doesn't necessarily mean your glasses prescription has changed.
Research has also linked prolonged near work with myopia development and progression, particularly in children, although the relationship between screen time and eyesight is complex.
If your vision regularly becomes blurry after working at a screen, an eye examination can help establish whether you need a prescription update or whether something else is contributing to your symptoms.
Does wearing glasses make your eyesight worse?
Let's clear up one of the biggest myths about glasses.
No. Wearing correctly prescribed glasses does not make your eyes weaker or dependent on glasses.
Glasses correct the way light enters your eyes so you can see more clearly. They don't weaken your eye muscles or cause your prescription to increase.
So why does your eyesight sometimes seem worse when you take your glasses off?
Once you've become accustomed to seeing clearly, returning to your natural, uncorrected vision can make the difference feel much more noticeable.
Your eyes haven't necessarily deteriorated because you've been wearing glasses. You've simply become used to clearer vision.
If your prescription has changed, your optometrist can explain what's happening and whether you need new lenses.
Why is my vision blurry with my old glasses?
Have you noticed that your old glasses no longer seem quite as effective?
Perhaps you're squinting at road signs, moving your book further away or struggling to see clearly at the end of the working day.
Your prescription may have changed since your last eye test. However, blurry vision can also result from dry eyes, dirty or damaged lenses, poorly fitting frames or an underlying eye condition.
If your glasses aren't providing the clarity they used to, it's worth arranging an eye examination rather than simply assuming you need a stronger prescription.
Can your eyesight get worse suddenly?
Most routine prescription changes happen gradually, but sometimes people notice a change in their vision much more quickly.
Sudden changes in eyesight shouldn't be dismissed as simply needing new glasses.
If you experience sudden blurred vision, a sudden loss of vision, new flashes or floaters, a dark shadow across your vision or eye pain, seek urgent medical advice. Sudden vision loss is a medical emergency.
For more gradual changes, an eye examination can help identify whether your prescription has changed and assess your eye health.
How often should your glasses prescription change?
There's no universal timetable for prescription changes.
Some people have a relatively stable prescription for years, while others experience more frequent changes, particularly during childhood or as they approach their 40s.
In the UK, adults are generally advised to have an eye examination every two years, although your optometrist may recommend more frequent appointments depending on your age, eye health, prescription and individual circumstances.
Children and people with certain eye conditions or health concerns may need to be seen more regularly.
And if you've noticed a change in your vision, you don't need to wait until your next routine appointment to have your eyes checked.
Your eye test is about more than stronger glasses
It's easy to think of an eye test as a way to find out whether you need a new pair of glasses. But there's much more to it than that.
During an eye examination, your optometrist assesses your vision, checks your prescription and examines your overall eye health.
They can investigate changes in your eyesight, look for signs of certain eye conditions and recommend the most appropriate next steps.
Whether your prescription has changed significantly or barely at all, regular eye examinations are an important part of looking after your long-term eye health.
Not sure whether your prescription has changed?
If your glasses aren't feeling quite right, you're struggling to see as clearly as before or it's simply been a while since your last appointment, we're here to help.
At Eye Emporium, our team can assess your prescription, check your eye health and help you find the right solution for your vision.
