Laser Vision Clinic Central Coast has become the first laser clinic in New South Wales, and the third in Australasia, to offer SMILE flapless, keyhole laser vision correction of myopia and myopic astigmatism. SMILE stands for SMall Incision Lenticule Extraction. The procedure uses the Visumax femtosecond laser made by Carl Zeiss Meditec to perform a complete refractive correction, with no use of an excimer laser. The Visumax laser cuts a convex lenticule of tissue in the mid-corneal stroma and a small 4mm long side incision. The lenticule is then removed through the side incision, resulting in flattening of the central cornea and correction of myopia.
Gosford refractive surgeon, Dr Anil Arora, who has been performing the surgery, is very enthusiastic about the technique.
“I am absolutely delighted to be able to offer SMILE to my patients,” he said. “The potential to do femtosecond-only refractive surgery was the reason I initially bought a Visumax laser some years ago, even though it was significantly more expensive than competing lasers. No other femtosecond laser has the capability of performing this type of surgery. It has become my procedure of choice for younger myopes and I believe it has a number of advantages over conventional LASIK surgery.”
Dr Arora believes that conventional LASIK is an excellent and proven procedure, but cutting of a corneal flap has some important consequences. The anterior third of the cornea is the strongest part of the cornea, and this strength is significantly reduced by cutting of the LASIK flap which typically involves side cuts into the top 15 – 20% or so of the cornea. This can be of particular concern with large corrections where preservation of the biomechanical stability of the cornea is paramount. In addition, corneal innervation is damaged by cutting of the flap, which may predispose patients to dry eye issues. The flap is also vulnerable to trauma which may result in displacement or loss of the flap. This can be a significant concern for active younger patients.
By contrast, SMILE involves a lamellar cut within the deeper stroma with only a small 4mm superficial side cut. Lamellar corneal incisions have little effect on corneal stability in contrast to the side cuts in LASIK surgery. Because the lenticule is cut under a 120 micron cap, the strongest anterior part of the cornea is minimally affected. A recent paper in the Journal of Cataract and Refractive Surgery has confirmed that SMILE has less effect on corneal stability than conventional LASIK.
Because only a small superficial incision is made in SMILE, there is less damage to corneal innervation than with LASIK. This in turn should result in less dry eye problems after refractive surgery. Finally, in the absence of a corneal flap, there are no concern about displacement or loss of the flap from corneal trauma.
Other advantages compared to LASIK, which have been demonstrated in clinical studies include better stability and predictability of outcomes, especially for higher corrections.
“SMILE is a really cool procedure,” Dr Arora said, “It works as well for -10 dioptres as it does for -2 dioptres, it is a silent, no-smell surgery which takes between 4 and 5 minutes to complete, irrespective of the size of the correction, about the same time to complete as it takes me just to cut and lift a LASIK flap so it is easier for me and my patients. It really has all the advantages of LASIK with none of the disadvantages. With no flap, there are no potential flap-related complications. This is a big plus for active young people, particularly if they are involved in sports or martial arts with a risk of ocular trauma. Carl Zeiss Meditec is continuing to refine and develop SMILE and I think this will only continue to get better. It’s the closest thing I know to a virtuous refractive surgery procedure.”
Posted: September 6, 2014
