It takes time to recover from PRK. Can't avoid it.
And it’s all because PRK creates a controlled “injury" to the surface of the eye.
During PRK, the surface layer of the cornea, called the epithelium is removed allowing the laser to treat the rigid structural part of the cornea underneath called the stroma. This is the one underling difference between PRK and lasik; lasik creates a flap instead to get to the stroma. This single difference means a longer recovery time for PRK.
The recovery after PRK can be broken down in a few distinct phases
- Healing of the epithelium surface layer
- Improvement in vision / Prevention of haze
Of course, nobody likes the recovery after PRK. So let’s break down what to expect for each step and what can be done to speed everything up.
Healing Of Surface
In general, it takes about 4 days on average for the epithelium on the surface of the eye to heal over after PRK.
During this 4 day window, it is very common to have discomfort and blurry vision. Normally a scratch on the surface of the eye would be MUCH more painful; the cornea is the most sensitive structure in our body. But a contact lens helps reduce this pain to a much more tolerable discomfort.
But this large scratch steadily heals up over the course of the four days. In fact, after a small lag time, the epithelium regenerates at a constant rate of about 0.1mm per hour! So generally, how long it takes to heal up after PRK depends on how much epithelium was removed in the first place. And for PRK treatments, somewhere around 7.5mm to 8.0mm of epithelium are removed. By doing some mental math, this puts us somewhere around 3-4 days for the surface to heal over.
Check out How Long Does A Scratched Eye Take To Heal? to learn more
How To Promote Healing
So what can you do to make things go quicker?
First, we want to try to prevent any delay in healing
- Inflammation can interfere with the ability of the epithelium to regrow. It is very important to prevent inflammation on the eye. This means taking the prescribed steroid or NSAID eye drop while the eye is healing. This means also taking care of another big cause of inflammation: Dry eye. Using frequent preservative free artificial tears helps prevent the buildup of inflammation promote the best healing of the surface.
- Don’t rub the eyes! Causing the scratch to get bigger by rubbing the eyes certainly can delay healing. If your surgeon gave you goggles or eye shields to wear at night, wear them to prevent inadvertent rubbing of the eyes. Rubbing the eyes can also potentially cause you to rub the contact lens out of the eye. This WILL cause pain. More reasons to avoid rubbing the eyes after PRK.
Can we encourage healing?
- Take your vitamins! There is some evidence that taking some supplemental vitamin E can help encourage healing. Vitamin E acts as an antioxidant and may help decrease damage from free radicals caused by the injury to the epithelium.
But while you can provide the best environment for the eye to heal, ultimately you still need to give time and wait it out for the first few days after PRK.
Improvement Of Vision / Prevention Of Haze
After the first week, we’re through the first recovery phase of PRK. The surface of the eye has healed over; discomfort has significantly decreased, vision has steadily improved. But we aren’t done yet.
It takes time for the vision to fully sharpen up after PRK. While you’ll be able to see after the first week, it can take about 3-6 months for the full clarity of PRK to be realized! During that time, it’s normal to have some fluctuation of vision and prescription, decreased sharpness and even some ghosting of vision.
While waiting, there are two things you can do something about to improve this vision as much as possible.
- Treat dry eye
- Prevent the development of corneal haze
Dry Eye
As we saw, having dry eyes and inflammation can slow how quickly the surface of the eye heals over. But dry eye also affects the way we see.
On the surface of our cornea is a tear film. This tear film protects the cornea and prevents it from drying out. When the tear film is good and robust, it is perfectly smooth and clear.
If this tear film dries out or evaporates away too quickly, it no longer smooth and clear. It becomes irregular and vision becomes more blurred.
However, after every blink, the eyelids make this tear film smooth again. So what happens is that each blink can sharpen up vision but a few seconds later when the tear film dries up again the vision becomes blurry. This leads to fluctuation of vision.
But in addition to fluctuation of vision, if the cornea develops some dry eye damage, it will also cloud vision and make things blurry.
The solution? Aggressive treatment of dry eye. This is especially important after ANY laser eye surgery. All laser eye surgeries will cause some increase in the amount of dry eye. PRK patients aren’t any exception. The inflammation that builds up after PRK causes an increase in the amount of dry eye.
The best way to treat dry eye? Again, frequent use of preservative free artificial tears. Learn more about how to choose the best artificial tears: These Are The Best Eye Drops After Lasik (also can apply to PRK).
Check with your doctor if you have significant dry eye. There are other dry eye treatments that may benefit you.
Haze
In the past, haze used to be more of an issue with PRK. Essentially, the corneal responded to the “injury" caused by PRK by becoming a little more cloudy.
Check out What YOU Can Expect With Post PRK Haze to learn more.
There are actually two different categories of haze. One happens early on and the other happens well, later on.
Early haze happens to pretty much almost everyone. But early haze also happens to be mostly insignificant. It may be part of the reason why vision takes a little longer to recover with PRK. But there isn’t really anything to do about early haze.
Late haze, however, is the haze we want to prevent. This haze can cause glare and blur vision more, can cause some of the prescription to wear off, and takes much longer to resolve.
There are various things which increase the risk of late haze. Most of which you can’t change.
- Having high prescription or astigmatism treated with PRK
- Being young
- Being treated with an old generation laser
- Not being treated with a special medication called mitomycin C at the time of the treatment (most surgeons will use this medication)
Despite not being able to change the above, all in all the risk of late haze is quite low. For those with high prescriptions the risk is about 1% (and even lower at 0.1% for those with smaller prescriptions).
But of course we want to speed up the recovery after PRK and prevent as much haze as possible. So what can be done?
- UV light is a known risk. Having a lot of sun exposure can lead to the development of haze post PRK. Fortunately there is a good easy treatment: sunglasses. Wear sunglasses whenever outside for at least the first year to protect the eyes from UV light. Make sure you look for sunglasses that are rated UV400 protection. This means they block 99-100% of all UVA and UVB light.
- Finally, continuing to take your vitamins may also help! Especially vitamin C. Turns out ascorbic acid or vitamin C can actually absorb some UV light. Taking extra vitamin C before and after the procedure can reduce the risk of haze. However, this may or may not matter as much anymore with the more routine use of that special medication mitomycin C.
Summary
The recovery after PRK can be broken down into two steps. During the first step, the epithelium on the surface of the cornea heals over. This takes time. Reducing inflammation and preventing any additional injury can keep this step from becoming delayed. Following that, the vision continues to sharpen up. Treating dry eyes with artificial tears and wearing sunglasses to prevent the development of haze are two big ways to speed up the recovery of vision after PRK.
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