What Is The EVO ICL?
The Visian ICL is a very elegant way of correcting vision. Other vision correction techniques such as lasik rely on permanently changing structures of the eye to correct vision. The Visian ICL instead is an implantable lens used to correct vision. But all technologies evolve, and the ICL evolved to become the EVO Visian ICL.
The EVO Visian ICL is the next generation of Visian ICL. This lens incorporates a tiny central hole. This small change improves the ease and safety of the ICL.
EVO Visian ICL - Image ⓒ Staar Surgical, used with permission
Now I know what you are thinking. Can a tiny central hole do all that? Let's take a look at how ICL works and how the EVO Visian ICL does things differently.
What is ICL surgery?
ICL surgery is a vision correction procedure different from others like lasik in that it correct vision by implanting a lens within the eye. The cool part about ICL is that this lens allows for the correction of very high amounts of prescription. It does it while at the same time being reversible.
(see also Learn Exactly What Is ICL Surgery)
Issues with eye pressure
To correct vision, the ICL sits just behind the iris or the colored part of the eye and right in front of your own natural lens. Surrounding the ICL and the iris and filling the eye is a liquid called aqueous humor. This aqueous maintains the pressure of the eye. It is created behind the iris and flows through the pupil to drain out of the eye in front of the iris.
Because the ICL sits behind the iris, it can block the flow of this aqueous and prevent the aqueous from draining out of the eye. This would cause the eye pressure to go very high (and cause lots of problems)! (see also What Can Be Some Big Problems After ICL Surgery?) So for the original ICL, a laser was used to create a small hole through the iris.
This laser procedure (called a laser iridotomy) was done prior to the ICL surgery, requiring a separate visit. In addition, this laser procedure can be uncomfortable. The eye drops used during the laser procedure can blur vision and cause a headache. The laser treatment itself has a very weird sensation.
While this laser procedure works to prevent any pressure issues with the ICL, it's makes the ICL process and experience more difficult. In an ideal world, this laser procedure would be unnecessary.
How EVO ICL does things different
There isn't a whole lot different with the EVO Visian ICL. It still has the proven design of the previous generation of ICL and does an exceptional job of correcting vision. It still comes in toric powers to correct astigmatism. There is just one simple difference: the EVO Visian ICL incorporates a central hole in the lens.
This central hole allows for the aqueous from behind the ICL to pass through the ICL lens and into the front of the eye before draining out. The ICL can no longer block the flow of this aqueous!
This eliminates the need for any other laser procedures prior to the ICL surgery. It eliminates that extra visit. No longer do you have to go through an uncomfortable procedure prior to getting your vision corrected with ICL. I think we can all agree that that's a good thing.
This extra hole improves the safety of the ICL
The improvement in aqueous flow that the central hole of the EVO Visian ICL not only prevents pressure issue with the eye, but it also prevents another potential side effect of ICL. One potential long-term issue with the ICL is the development of a cataract.
A cataract is a clouding of the natural lens within the eye. This clouding causes blurred vision.
The ICL lens sits close to your natural lens. If the ICL lens sits too close, it can prevent your natural lens from getting essential nutrients. This can cause the natural lens to get "sick" and become a cataract. While cataracts can be treated with cataract surgery, the most ideal course is to prevent cataracts in the first place.
The central hole of the EVO Visian ICL improves the flow of nutrients around the natural lens. Aqueous is essential forced to move around the lens and provide nutrients on its way through the ICL and out in the front of the eye. This keeps the lens healthy and prevents cataracts from developing.
Multiple studies have confirmed that the EVO Visian ICL has a much much reduced incidence of cataract development. In fact, the chance of a cataract after EVO ICL may be close to zero! While the risk of cataracts were low before the EVO, anytime you can reduce something to near zero can be considered a success.
Does that extra hole have any side effects?
This hole with the EVO Visian ICL is within the center of the lens. This prevents the iris from covering up the hole (of note, the EVO Visian ICL does have two additional holes on the side; but those can be covered by the iris from time to time). Because this hole is in the center, you are looking through this hole all all times. Will this hole affect vision?
Everyone after ICL will have some degree of night time vision symptoms (see also What Are The ICL Surgery Side Effects?). Only the center circle of the ICL actually corrects vision. When the iris dilates past the center circle, light passes around instead of being focused by the ICL. This creates a halo effect.
But the EVO Visian ICL can actually create another ring-like effect in vision from the center hole. This is in addition to the other night time vision symptoms they can experience. But despite this additional effect in the vision, the overall night time vision symptoms remain very similar to what patients experience without having that center hole. And thus, the center hole of the EVO Visian ICL doesn't add any significant additional side effects.
And those night time vision symptoms from ICL? Those continue to fade away over the course of the first few months as the brain adjusts to the new ICL vision in a process called neuro-adaptation.
The Visian ICL was already a great way to correct vision. The EVO Visian ICL evolves the treatment even further to make ICL surgery even better. The presence of the central hole within the EVO ICL improves the safety and eliminates annoying steps prior to the surgery.
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