What Is A Toric ICL?
If you're here, you may be a little confused by the word toric (or perhaps the word ICL). Sometimes eye procedures throw in a seemlingly random and confusing word. After-all, I'm sure you don't hear the word toric being thrown around all too often. But the word toric exists all through the eye world including with ICL eye surgery. And it means a very specific (and easily understood) thing.
Let's start at the basics:
What is ICL?
Before understanding what the toric ICL is, we have to understand what the ICL is. ICL surgery is a vision correction surgery to get out of glasses and contact lenses. It's similar to popular surgeries such as lasik in this one definition. It's much different from laser eye surgery in that ICL surgery implants a new lens within the eye itself (see also What Is ICL Surgery?). This lens has the prescription necessary in order to correct a very large range of nearsighted-ness. In fact, for patients with severe nearsightedness, ICL opens up the door to the opportunity of correcting their vision.
Initially, when the ICL was introduced, it was incapable of correcting astigmatism.
Wait a sec, what is astigmatism?
In a perfect world, everyone's cornea would be shaped like a perfect lens. A perfect lens has a perfect dome shape in order to funnel and focus light into a single point. But alas, life and corneas aren't perfect. Some people can have corneas that are shaped more like footballs and less like a dome. On a football, one side is flatter and one side is steeper. This happens on corneas as well. The trouble with corneas shaped like footballs is that light that enters the steep side of the cornea gets focused at a different point than light that enters the flat side of the cornea. This creates blurry vision. This can create double vision or ghosting. This is astigmatism.
This is a football; Photo by Dave Adamson on Unsplash
If you have astigmatism, you are already likely correcting it with glasses and / or contact lenses. A glasses prescription consists of three different numbers. The last two numbers determine how the astigmatism is corrected. One of those numbers is how much astigmatism you have, called the power (how much of a slope difference exists between the flat part of your cornea and the steep part of your cornea). The other number determines the direction of the astigmatism, called the axis (where does the steep or flat part of the cornea point on a 360° scale; actually really only 180° because like a football, the steep side exists on opposite sides of the cornea). With these numbers, the glasses are able to balance out cornea curve and correct vision.
But there are more ways to correct astigmatism than just with glasses or contact lenses.
And as you guess it, this is where "toric" enters the scene. A toric lens is a lens capable of correcting astigmatism. You see this with contact lenses. Toric contact lenses correct astigmatism while standard contact lens do not. You also see this with ICL. A toric ICL works to correct astigmatism.
Toric ICLs are capable of correcting astigmatism up to +4.00 diopter power (the vast majority of astigmatism people have fall into this range). If you have +2.50 astigmatism, a lens is built for you. If you have +1.50 astigmatism, same thing, a lens is built for you. For each level of astigmatism up to +4.00, a lens is built entirely for that level of astigmatism. It's a truly custom vision correction solution.
How is toric ICL surgery different?
Correcting astigmatism with a toric ICL isn't more complicated than using a standard ICL. The surgery is the exact same except for one additional step. As I mentioned, astigmatism has two parts: the first part is the power or how much astigmatism you have; the second is what direction the astigmatism lies or the axis. After the surgeon places the ICL within the eye with the correct astigmatism power, the surgeon must then rotate the ICL to align it up with the correct axis. That's the additional step.
This rotation is actually quite minimal as well. The ICL is designed to sit horizontally in the eye; the sizing of the ICL is developed from horizontal measurements of the eye. But what a quandry! Astigmatism can exist in 180°. What if you need to rotate the ICL to sit vertically to correct astigmatism? The Staar, the makers of the toric ICL already thought of this problem. Not only do you have ICLs with different powers of astigmatism, different ICLs are also manufactured depending on the different directions the ICL need to point! Because of this, surgeons never need to rotate the toric ICL more than 22° (and frequently less than 5°) to correct your astigmatism. Toric ICL really adds minimal changes to the actual ICL surgery.
Anyone who has worn toric contact lenses has come across a typical problem: Toric contacts can rotate on the surface of your eye. When the astigmatism correction rotates away from the axis of your astigmatism, things get blurry. Fortunately, toric ICL doesn't have this problem. Once a toric ICL is in place, it's very rare for it to move or rotate around. The ICL is made out of a very very flexible material (called collamer). This flexibility gives the ICL extra grip in place once the lens is within the eye. It just doesn't move once it's in place. Which means you don't have to worry about fluctuating blurry vision like with contacts.
Toric ICL works very well to correct vision
ICL surgery is a very accurate procedure (and quite impressive given how much prescription ICL surgery is capable of treating). Toric ICL is no exception. The Toric ICL works very well to correct astigmatism. There is a caveat, if you have more astigmatism than what ICL is capable of treating (greater than +4.00 diopters of astigmatism), than you more than likely will have some remaining astigmatism left over (which can be frequently treated with a lasik enhancement to eliminate it all).
Many surgeons are already using the toric ICL even if they don't mention it. It's just a no brainer to correct all the prescription that the ICL is capable of correcting. But the toric ICL does come at a slightly increased cost from the manufacturers. Sometimes the practice incorporates this extra cost into overall average ICL pricing. Sometimes the practice breaks the cost down more a la carte. In either case, it doesn't hurt if you have astigmatism to confirm that you are getting the toric ICL with your ICL surgery. You won't to pass up the ability to correct even more vision with ICL.
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