One unique feature of cataract surgery is that it will change the prescription of your eye. The prescription of your eyes before cataract surgery won’t necessarily be the same prescription that you have after cataract surgery.
This is great news for those who had high prescriptions before cataract surgery. Cataract surgery can eliminate that high prescription.
This applies to glasses as well - your old glasses before cataract surgery may not work the same and correct your vision after cataract surgery. In some cases, you may not even need glasses at all. Or you may just require a pair of reading glasses to see up close. But there are a few situations in which your old glasses can work for you.
But before we get into that, let’s first review what causes you to have eye prescription and how cataract surgery changes that.
Background On How Your Old Glasses Correct Vision
Before cataract surgery, there are two major contributors to the prescription of the eye:
- The cornea, which contributes about ⅔
- The natural lens, which contributes the remaining ⅓
Light is first focused by the cornea before passing through and focused by the natural lens.
Ideally, the combined focusing of the cornea and the lens allows light to focus perfectly on the retina in the back of the eye - giving perfect distance vision. (up close reading vision to come)
But if you need glasses prior to cataract surgery, then your cornea and lens don’t completely bring things in focus. And adding a pair of glasses to the mix takes care of the remaining focusing need.
This prescription can change slightly over time but not by much. However, when cataracts develop, this prescription can change a whole lot more.
If you are nearsighted, farsighted or have astigmatism, this is what the glasses are doing. Your eye can’t focus everything perfectly by itself and so the glasses make up the difference.
Glasses also correct up close vision
One thing that happens to everyone is a loss of the ability to see up close, called presbyopia. This often also requires glasses.
Interestingly, the natural lens inside our eye is capable of changing shape. When we are young, this lens becomes thicker when we look up close and will change the way it focuses light to allow us to read.
How the eye focuses up close, image by MikeRun, CC BY-SA 4.0, via Wikimedia Commons
But this lens and the mechanism that controls it become weaker as we get older. During our forties, it becomes progressively harder and harder to see up close.
- Individuals who have never needed glasses before start to need reading glasses
- Nearsighted individuals may still be able to see up close without their glasses, but will need to go into progressive or bifocal glasses to be able to read up close with their glasses.
How Cataract Surgery Changes Things
Going into cataract surgery, there is a good chance you needed glasses for one reason or another. But coming out of cataract surgery, things can be dramatically different.
The natural lens (the one that contributed ⅓ of the prescription of the eye) is what gets cloudy and becomes a cataract. And this cataract is removed.
If that is where the surgery ended, our eyes would be missing about ⅓ of the ability to focus light (the contribution of the natural lens). So the focusing power of the natural lens is replaced with an artificial lens instead.
But we don’t have to settle with the same power that your natural lens came in (you know, the focusing power which left you nearsighted, or farsighted). During cataract surgery, your cataract surgeon can pick any power of this lens.
So instead of being nearsighted or farsighted, the power of this artificial lens can be selected to give you perfect distance vision instead.
Your vision will change after cataract surgery.
Your OLD Glasses After Cataract Surgery
Because cataract surgery will change the prescription of your eyes, there is a really good chance that your old pair of glasses WON’T work the same as they did before cataract surgery.
But there are a few instances in which you may actually be able to use your old pair of glasses:
In between surgery on first and second eye
Your old glasses will still correct the vision for the eye that hasn’t had cataract surgery yet. You may be able to pop out the lens of the eye that just had the cataract removed and have the glasses work to get you by.
Whether or not this works depends a large degree on how much prescription you have. If you had too high of a prescription before cataract surgery, than this won't work.
Check out What To Do About Glasses After Cataract Surgery On One Eye to learn more
You only needed reading glasses before cataract surgery
If you already had perfect distance vision before cataract surgery, then having perfect distance vision after cataract surgery won’t cause any change in your prescription. The same may also apply to your reading vision as well.
The new lens placed during cataract surgery can’t change shape. (This is similar to how our natural lens can’t focus up close anymore once it loses the ability to change shape). Because of this, a typical lens after cataract surgery will still require reading glasses afterwards.
And if you only needed reading glasses beforehand, the same reading glasses you used before surgery can be used after the surgery as well.
Note: A ‘typical’ lens for cataract surgery will require reading glasses afterwards; but certain premium cataract lenses can simultaneously correct for distance and up close vision. Check out Your Complete Guide Of Lenses For Cataract Surgery to learn more
You wished to remain nearsighted after cataract surgery
Remember when I said the surgeon can pick any power of the artificial lens? Well, this means the prescription can be set at pretty much anything. While most people desire to have good distance vision after cataract surgery, some nearsighted people prefer to keep that nearsighted vision after cataract surgery (which allows them to see up close without glasses).
So instead of correcting for good distance vision after cataract surgery, you can instead stay nearsighted.
Some nearsighted prescriptions are better than others. For example, being severely nearsighted isn’t as good as being mildly nearsighted; you have to hold things too close to see and your distance vision is significantly worse. So surgeons aren’t going to necessarily aim to match your preexisting prescription, they are going to aim for a mild nearsighted prescription since that will provide the best all around performance.
But if you happen to be mildly nearsighted before surgery, your glasses prescription may be close enough to your mild nearsightedness after cataract surgery. And so if you can see well enough with it, great!
Preexisting astigmatism
Finally, let’s say you had a decent amount of astigmatism before cataract surgery. And the astigmatism is the only prescription you have; you don’t have any extra nearsightedness or farsightedness.
If you opt not to correct this astigmatism surgically, you will still have this astigmatism after cataract surgery. And this may be close enough to what you had before cataract surgery to allow you to use your old glasses.
But it isn’t too common that this works well enough to be happy with vision.
When To Get New Glasses
If you don’t fall into any of the above categories, you will be needing to get a new pair of glasses after cataract surgery (unless you used one of those special lenses to get you out of glasses).
In most cases, you don’t need to wait very long. For many, the prescription of the eye stabilizes pretty quickly within about a week or two after cataract surgery. Also check out Exactly How Long Does It Take For Vision To Stabilize After Cataract Surgery.
But if you only need to get reading glasses, that can done at ANY time after cataract surgery. Reading glasses are cheap and if the prescription isn’t fully stable, it isn’t a big deal to buy another pair.
Check out How To Pick The Best Reading Glasses After Cataract Surgery to learn how to get the best pair for your eyes.
Summary
Cataract surgery will change the prescription of the eyes. Because of this, chances are your old pair of glasses won’t work well afterwards - unless you fall into a few distinct scenarios or are in between getting the cataracts removed in each eyes. But if you do need new glasses (and especially if you need reading glasses), you don’t have to wait long until you can get your vision corrected.
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