What Other Types of Refractive Surgery Are Available?
There are several other types of refractive procedures besides LASIK, including SMILE, ICL, and PRK. A description of each is included below.
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What Is Small Incision Lenticule Extraction (SMILE)?
Small incision lenticule extraction, or SMILE, is a procedure designed for those with myopia, or myopia with astigmatism. Importantly, it cannot correct hyperopia like LASIK can. The procedure itself works by removing a small contact-lens shaped piece of the cornea. This piece, called a lenticule, is removed through a small incision cut in the side of the cornea. Hence the name, small incision lenticule extraction. The patient expericne of SMILE is smilar to LASIK, with SMILE taking slightly longer to complete. They are both one day procedures in which both eyes are corrected at the same time. The removal of the lenticule flattens the cornea, which can correct myopia and some forms of astigmatism. Smile is capable of correcting up to -10 diopters of myopia or up to -5 diopters of astigmatism, making it very comparable to LASIK. The outcomes of the procedure are also very comparable, with long-term studies showing that visual acuity, regression rates, and other visual metrics were no different between SMILE and LASIK.Where they differed was in the in post-op dry eye and the reinnervtion of cornea nerves, both of which favored SMILE. This appears to be because the small incision disturbs less of the cornea than a LASIK flap. The smaller cut also gives the cornea greater post-operative strength, which can help it resist any injuries bumps.
The disadvantages of SMILE include its inability to correct hyperopia and higher-order aberrations (HOA). HOAs include night glare, blurring, halos, starburst, and double vision. SMILE may actually exacerbate these conditions.
What Is ICL?
An ICL, or implantable collomer lens, can be thought of as a contact lens placed behind the lens of the eye to help correct vision. Like a regular contact lens, an implantable lens refracts light so that it better focuses on the back your eye, called the retina. For this reason, it can correct both hyperopia and
myopia, with and without astigmatism. The only kind of lens on the market is called a posterior chamber phakic intraocular lens (pIOL), which is placed in the space behind the lens of the eye, called the posterior chamber. Since it has to be place intaocularly, the procedure is much more involved than LASIK, PRK, or SMILE.
The surgery itself is very similar to cataract surgery. The ICL procedure is painlessly performed under anesthesia, usually in under 30 minutes. The surgeon will create a small opening in the cornea, the clear front layer of the eye, where the lens will be inserted. The packaged ICL is pushed through the opening and then unfurls in the eye. The ICL position is adjusted until perfection, and then the procedure is over.
The advantage of an ICL over LASIK is that is can correct a much higher degree of myopia. Those with greater than -12 diopters can not be corrected by LASIK. However, the ICL can fully correct up to -15 diopters and can reduce the nearsightedness in those with up to -20. LASIK is also irreversible because it is reshaping the corneal surface, which is not true of ICLs. Although the lens are meant to stay in forever, if the need arises, they can be removed.
The risks and complications are different as well. The ICL procedure does not involve the removal of corneal tissue, which is what leads to many of the complications seen in LASIK, including dry eyes. However, the ICL procedure is eye surgery which can lead to complications not seen in LASIK, including rotation of the lens and an increased risk of Glaucoma. It should be noted that these are exceeding rare.
What Is PRK?
Compared to SMILE and ICL, PRK is the most similar to LASIK. In fact the main difference is simply how they reach the stroma of the cornea. The stroma is the strong middle layer of the cornea that is ablated in both PRK and LASIK. In order to get at it, the upper layer, called the epithelium, must be moved out of the way. In LASIK, this is done through the creation of a flap, which is flipped up to reveal the stroma. In PRK, the epithelial layer is simply removed. While this may sound worse, it actually preserved much more of the structural integrity of the stroma. This makes it advantageous for those with thinner corneas, who need to protect as much tissue as possible. The decision between LASIK and PRK, should be discussed with your surgeon, as the answer depending on your general eye health
What Is a Bladeless Lasik?
Bladeless LASIK is the most common type of LASIK performed in the US today. When LASIK first began, the flap wasn’t cut with a laser, but with a blade called a microkeratome. This technique was superseded by an eximer laser to cut the flap instead. It’s always good to check with your surgeon to makes sure the procedure uses a laser instead of a microkeratome.
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While LASIK is undoubtedly the most common type of refractive surgery. There are several others that may be better suited for the indivudal patients needs. For example, those with a predisposion to dry eyes may be better served by SMILE, which has a lower risk of exacerbating dry eye symptoms. For those with extereme prescriptions, LASIK may not be able to correct it fully, and so an ICL may be a better choice. As mentioned above, those with thinner corneas may benefit from PRK over LASIK.
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Try not to base your decision on price as it can lead to unsatisfactory results when sacrificing quality for a lower price. With each surgeon you consider, verify their credentials and licensing which can be looked up online. Also determine if they are adequately experienced. An experienced lasik surgeon should have performed over 10,000 lasik eye surgeries and be performing lasik on a regular basis.