Joel Hunter, MD Refractive Surgeon, Hunter Vision Updated 04/09/21 11:45 AM
Your cornea sits on the front of your eye. It is the front of your eye. It’s made out of the same collagen that the white of your eye is made of, only it’s clear instead. Why does that matter? Because collagen can stretch. And the looser the collagen is woven together, the more it stretches.
That’s why we want the collagen in the cornea to be tight and strong. It’s part of the wall of the eye, and the eye has a certain amount of pressure to keep it “inflated” so it doesn’t look like a raisin. The white of the eye (the sclera) is strong like leather on a baseball, so if there’s going to be a problem with weak, loose collagen anywhere, it’s going to be in the cornea.
And that’s exactly the problem in keratoconus. The collagen is too weak — too loose — to withstand the natural pressure in and around the eye. So it slowly (over years) starts to bulge a bit. Not in an obvious way that would make you look bug-eyed, but subtly, microscopically. It’s like a very mild version of having a weak spot in the wall of a tire. It starts to balloon out in the area of weakness.
As you can imagine, a lens (because that’s what the cornea acts as) with an asymmetric bulge in it is going to have some problems. It creates astigmatism, blur, and distortion. This is why people with keratoconus have difficulty seeing well.
There are two ways of fixing this problem. One we do at Hunter Vision, and one we don’t. The first line treatment for this is a contact lens that corrects the blur. It’s a contact with a nice, astigmatism-free curve to it, and it vaults over the bulge in the cornea to correct the vision. It works shockingly well. A specialty contact lens expert, like Dr. MacDonald, prescribes those and they are usually pretty life changing!
The second way to fix this problem is with collagen crosslinking. We don’t do that here at Hunter Vision, but I’m a big fan of it. There are many places across the US and the rest of the globe that do crosslinking with great results. The idea behind it is that it tightens the loose collagen, while keeping the clarity of it. Again, the results can be life changing!
If you wonder what treatment might be best for you, feel free to come see us! As cornea specialists, we see our fair share of keratoconus. It’s a frustrating diagnosis to get, but so much better nowadays than 20 years ago! There are truly great treatments that can help in a dramatic way.