SMILE Eye Surgery

28 Nov SMILE Eye Surgery

The FDA approved the SMILE eye surgery in 2016 for the correction of myopia (nearsightedness) and astigmatism in the United States, but is has been is wide use in Europe since 2009.  Worldwide over 2 million SMILE procedures have been performed.  The SMILE procedure goes by several different names:  ReLEX SMILE, SMILE LASIK, and Small Incision Lenticular Extraction.

Refractive Eye Surgery

Refractive procedures use laser or intraocular lenses (IOLs, Phakic IOLs) to reduce the need for eye glasses.  For example, myopia (near sightedness) is an eye disability where individuals cannot see distant objects without glasses.  This happens because their eye is too long or their cornea is too steep.  SMILE, LASIK , and PRK are eye laser procedures that can correct this disability by flattening the cornea so that the eye can properly focus for far vision.  LASIK, SMILE, and PRK are all fantastic ways to treat myopia and astigmatism.  In fact, I had laser surgery on my eyes 20 years ago and have loved it.

In this post I will focus on LASIK and SMILE Eye Surgery, the two rapid healing procedures.  Let’s talk first about LASIK, then SMILE, and then compare the two procedures.

LASIK

With LASIK, a thin flap is created by a femtosecond laser.  This flap is elevated and then an excimer laser is used to vaporize away a small lenticule of tissue.  This flattens the cornea.  The thicker the lenticule, the more myopia is treated.  The flap is then repositioned and allowed to heal back in place.  An average cornea would be around 540 microns thick.  Another way to describe LASIK would be to consider it like a 540 page book.  The top 110 pages are opened up like the first 110 pages of the book.  Then the next 50 pages are removed and the first 110 pages are then closed back in place.  The overall weakening would be 110 plus 50 or 160 pages of the total 540 page book. This leaves 380 pages untouched which is considerably more than enough remaining strength for good candidates.

SMILE Eye Surgery

SMILE is an acronym.  The SM is for Small.  The I ins for Incision.  The L is for Lenticular and the E is for Extraction.  This acronym explains what SMILE is.  The femtosecond laser creates a small lenticule inside the cornea.  This lenticule is removed through a small incision which flattens the cornea.  Using our book analogy, 50 pages of the total 540 pages are removed through a small opening so the overall weakening is approximately 50 pages of the 540 total pages. 

SMILE Eye Surgery vs LASIK

Both procedures are outstanding for appropriate candidates and most patients could appropriately choose either and be pleased with their results. Smile leaves the cornea stronger^1,2 and there is less chance of dry eye.^3,4 A surgeon that offers both SMILE and LASIK would be in the best position to help you decide which procedure will be ideal for your eyes.

eusis. J Cataract Refract Surg. 2014;40(6):954-962.
Seven I, Vahdati A, Pedersen IB, et al. Contralateral eye comparison of SMILE and flap-based corneal refractive surgery: computational analysis of biomechanical impact. J Refract Surg. 2017;33:7:444-453. 
Denoyer A, Landman E, Trinh L, Faure JF, Auclin F, Baudouin C. Dry eye disease after refractive surgery: comparative outcomes of small incision lenticule extraction versus LASIK. Ophthalmology. 2015;122(4):669-676.
Cai WT, Liu QY, Ren CD, et al. Dry eye and corneal sensitivity after small incision lenticule extraction and femtosecond laser-assisted in situ keratomileusis: a meta-analysis. Int J Ophthalmol. 2017;10(4):632-638.