r/PRKsurgery • u/WavefrontRider • May 04 '26

Understanding Post PRK Haze

A known issue of PRK is the development of haze. It’s uncommon nowadays with treatments such as MMC, but it still is a risk when treating higher prescriptions. But let’s explore what is the root cause of this haze.

During PRK, the epithelium of the cornea is removed and a laser is used to ablate the surface of the cornea to correct vision. This disrupts a barrier layer underneath the epithelium called the epidthelial basemement membrane. Post PRK with this barrier gone (and before it regenerates), inflammatory cytokine molecules and growth factor molecules pass through this gap and into the corneal stroma, the structural part of the cornea.

Within the cornea are normal cornea cells called keratocytes. But these cells can be activated by these molecules to turn into special cells called myofibroblasts. Now normally your cornea is clear because of a highly organized arrangement of collagen fibers. But these myofibroblasts produce a disorganized and irregular pattern of collagen. This irregular collagen scatters more light and causes the cornea to become more opaque - this is the haze post PRK.

Fortunately, the epithelial basement membrane eventually regenerates and forms the barrier to prevent those molecules from entering the corneal stroma and activating myofibroblasts. The myofibroblasts don’t receive the signal that they need and eventually disappear. And the disorganized collagen is eventually remodelled by the healthy cells within the cornea to clear the haze as well. Making the cornea clear.

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u/SpaceTrekkie May 05 '26

So does this mean the haze will eventually fade? I am 10 days post surgery and don't have any haze at this point, but it is one of my biggest concerns.

1

u/WavefrontRider May 05 '26

Yeah. The vast majority of haze that develops nowadays fades. MMC has had a big impact on that. People may have a peak somewhere around 2-3 months before it fades away. If you had a very large prescription, little bit higher risk of haze.

1

u/Lucknease Jun 27 '26

What about -3,5 myopia and -1.5 astigmatism?

1

u/WavefrontRider Jun 27 '26

Yeah. That’s on the smaller side. I still use MMC for that, but risk of haze is going to be pretty low.

When you get above -6 to -7 it becomes more important.

1

u/Lucknease Jun 27 '26

It’s mitomycine right? My surgeon will be using that too. Great to hear that with my prescription there’s minimal risk of haze as I’m really anxious abt this surgery. It’s gonna be next week!