When we look at something, light coming from that object travels into our eye. This light is focused on our retina which in turn sends signals to our brain to tells us what we are looking at.
But what happens if some of this light gets scattered before reaching the retina? What you see may still be in focus, but it just may become harder to see.
But what happens if it’s a lot of light? The more light, the more challenging it becomes to see. This is glare.
Simulated Glare in vision; generated image courtesy of VisionSimulations.com
Note in the above image simulation of glare that details around the brightest parts of the image become harder to see because of the excess light. This is what glare does. Feel free to play around with different settings yourself at the above link to see how glare affects vision.
Cataracts
A big cause of glare is cataracts. Cataracts develop when our lens becomes cloudy. This cloudiness scatters light. Depending on the type of cataract, this scattering can cause an excess amount of glare in our vision.
The good news is that cataract surgery fixes the glare from cataracts. After cataract surgery, levels return back to normal levels.
But what happens when they don’t?
Well then there must be some other cause of the glare.
There are a few common causes of excess glare even after cataract surgery. But fortunately, many of these causes have good treatments to reduce the glare and improve vision.
Residual Prescription
Glare is commonly confused with other problems with vision, especially at night-time when everything is harder to see. But before we get into “true" glare issues, lets first cover one very common cause of vision problems after cataract surgery. It is simply having residual prescription.
The prescription of the eye changes after cataract surgery. For many, this leads to a dramatic improvement in vision. Often times distance vision is clearer than before.
But cataract surgery isn’t perfect and as much as 1 in 20 can end up off-target after cataract surgery. This can cause some blurring of vision.
On top of that, if astigmatism isn’t corrected during cataract surgery, the astigmatism will also blur vision.
Technically, blurred vision is different from glare. Light just isn’t focused on the retina properly. But similar to glare, blurred vision can cause trouble with vision and especially when trying to see at night.
So, one simple fix to improve that “glare" is to correct that residual prescription. This is most commonly done with a pair of prescription glasses. But there are other surgical options For Fine Tuning Vision After Cataract Surgery to avoid needing a pair of glasses.
Dry Eye
So what’s the biggest cause of glare after cataract surgery? Surprisingly, it’s usually dry eye.
Dry eye is very common. With age (and also from the effect of medications), our eyes dry out more and more. This of course causes the usual symptoms of dry eye such as burning and the feeling like there is something in the eye. But dry eye also affects vision as well.
On the surface of our eye is a layer of tears - called the tear film. In healthy eyes, this layer is smooth and light passes through easily. But with dry eye, this layer can dry out. But it doesn’t dry out completely evenly and smoothly. It dries out irregularly. So instead of being a smooth surface, it becomes bumpy. This causes light to scatter when being focused in the eye; thus, dry eye causes glare.
This glare may even fluctuate. Immediately after blinking, our eyelids work like a squeegee to smooth out the tear film. This can temporarily fix vision and glare. But with bad dry eye, this tear film may dry out again a few seconds later causing the glare issues again.
Even if you don’t have dry eye before cataract surgery, you may develop a short term dry eye after cataract surgery.
Our eyes don’t like to be messed with (even if it’s a good reason such as removing cataracts). Anything we do to the eyes can cause extra irritation and inflammation and cause the eye to dry out more readily. Being exposed and drying out a little more during cataract surgery can do this. But even just taking the prescription eye drops before and after cataract surgery can irritate and dry the eyes a little more. (due to preservatives in the eye drops)
Because it’s difficult to avoid all drops after cataract surgery, this means that everyone will have some degree of irritation, inflammation and dry eye after cataract surgery to recover from. This means blurry vision and glare. Learn more about the recovery at Precisely How Long Does It Take To Recover From Cataract Surgery.
Treating Dry Eye
It’s relatively straightforward to treat dry eye. It just takes some work and time for everything to heal up.
- The easiest initial step is to add more tears on the surface of the eye. This is done through over-the-counter artificial tear eye drops. Look for preservative-free artificial tears for the most effect. Take these tears regularly throughout the day to encourage the eye to heal up.
- Using lid scrubs, warm compresses and taking omega-3 supplements can also help keep the eye from drying out for many people and these are all inexpensive and effective over-the-counter treatment options.
- For more severe dry eye, check with your eye doctor about other treatment options such as medications that can help the dry eye heal faster.
Cloudy Capsule
Moving on, there is another common cause of glare after cataract surgery.
Inside our eye, the cataract is suspended within a capsule bag. This same capsule bag is used to hold the new artificial lens after cataract surgery.
But sometimes this capsule bag can get cloudy. Microscopic cataract particles can remain after cataract surgery and grow on this bag. As this bag gets cloudy, vision can get cloudy; but first, what typically happens is the cloudiness of this bag causes light to scatter. Which causes…you guessed it, glare!
Cloudiness on the capsule bag after cataract surgery; image by Rakesh Ahuja, MD, CC BY-SA 2.5, via Wikimedia Commons
Developing a cloudy capsule is pretty common. And it can even happen years out after cataract surgery. If you were initially fine after cataract surgery and then start to develop worsening vision and glare, this is most likely the cause.
Read more about it at The BIGGEST Reason for Blurred Vision 2 Years After Cataract Surgery
Fortunately, there is a pretty easy fix for a cloudy capsule. The surgeon uses a type of laser in the office to make a small opening in that capsule and eliminate the cloudiness. This small procedure (called YAG surgery after the type of the laser used), is an easy, straightforward procedure with a very quick recovery to get rid of glare after cataract surgery.
Glare From The New Lens
After cataract surgery, an artificial lens is placed where the cataract used to be. Some lenses, however, WILL increase the amount of glare after cataract surgery.
Many people want to get out of glasses. And advances in the design of artificial lenses have improved our ability to achieve that goal with cataract surgery. Special lenses exist to provide good vision without glasses for not only seeing far away in the distance but also for reading as well.
In order to truly change focus between far away in the distance or up close, a lens needs to either change position or shape. A normal lens is only capable of focusing light to one spot; it is a single focus or monofocal lens.
Because a lens after cataract surgery can’t change position or shape, a standard lens is only capable of allowing you see at one focus distance (typically optimized for far away distance vision; making reading vision blurry).
But advanced cataract lenses employ certain optical tricks to allow light to focus at different points. This allows the lenses to simultaneously focus for not only far away in the distance but also to see on the computer and to read a book. Because these lenses can focus at different distances, they are called trifocal or multifocal lenses.
But these extra benefits don’t come without a few small effects.
The main one is that the simultaneous focusing of vision will cause some extra glare. When looking far away off in the distance, the other “focus points" of the lens will be causing some scatter of light. Same with reading up close. This scatter of light will increase glare after cataract surgery (and also cause some related halos and starbursts). Fortunately over time, improvements in these lenses have reduced glare, halos and starbursts from previous versions.
Can the glare go away?
But what happens to the glare from these lenses? The good news is that we adjust to much of it over time.
Our brains are pretty sophisticated. And it’s no exception when the brain processes our vision.
Gradually over time, the brain starts to learn that the extra glare, halos and starbursts from these trifocal and multifocal lenses are just extra “noise" in our vision. So gradually over time, the brain starts to subtract that extra glare from our vision. In essence, the extra glare becomes reduced as we become adapted to the new lens over time.
Read more about this fascinating process at Adjusting And Training Eyes After Cataract Surgery
And there isn’t really much required of us except to just continue to use our eyes!
Summary
Anything that causes light to scatter before it reaches our retina will cause us to have some additional glare. While most people after cataract surgery will have much improved vision and glare, glare can happen after cataract surgery for a variety of reasons. Fortunately, these different reasons often have relatively easy fixes.
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