Author: Dr Val Phua MBBS, MMed (Ophth), FRCOphth, FAMS
Photo by: Antonino Visalli
SMILE surgery is one of the options for laser vision correction. While many have heard of LASIK as an option to achieve glasses and contact lens freedom, not as many have heard of SMILE. What is SMILE surgery and how does it work?
SMILE stands for Small Incision Lenticule Extraction. Also known as ReLEx SMILE, It is a form of laser vision correction which is minimally invasive and does not require the creation of a corneal flap. With SMILE surgery, a laser is used to shape a thin piece of corneal tissue (lenticule) within the layers of the cornea. This lenticule is then removed via a small incision.
Before going for SMILE surgery, a detailed eye examination with specialised investigations are done to determine how suitable you are as a candidate for SMILE surgery. This includes checking the amount of refractive error in the eye as well as corneal scans to see how healthy your corneas are. Patients with specific conditions like irregular astigmatism or corneal ectasia are not suitable for SMILE surgery. Once it has been determined that you are a suitable candidate for SMILE surgery what happens next?
On the day of surgery, your eye is cleaned and made numb with topical anesthetic eye drops. This ensures that surgery proceeds painlessly. The SMILE machine is then placed on your eye and a vacuum is turned on. This keeps your eye still while the laser is used to fashion the desired corneal lenticule shape. It is important that during this period you remain calm and still because sudden violent movements in the eye can cause the vacuum to break and result in an incomplete creation of the corneal lenticule. During this stage, there is a short period where the focusing light disappears and this is normal so don’t worry about it. Once the laser is done doing its job, the corneal lenticule is then dissected out with a blunt instrument to complete the surgery.
After the surgery, antibiotic and steroid eye drops are given to prevent infection and to aid healing. Your doctor will usually review how your eye is healing at several time points. Typically at 1 day after the surgery, 1 week after the surgery and 1 month after the surgery. One of the benefits of SMILE surgery is that there is no corneal flap created, hence during the recovery period, eye rubbing (while not encouraged) will not result in complications like corneal flap dislodgement.
SMILE surgery takes place within the layers of the cornea and avoids a corneal flap and this translates to a potential decreased incidence of dry eye side effects as fewer corneal nerves are cut during the laser correction. Vision recovery is also fairly quick with many being able to see well within a few days after surgery and can even carry on with most of their normal activities aside from swimming.
As with all other forms of surgery, SMILE surgery has potential side effects as well. This includes dry eyes, glare and halos, under and over correction of the refractive error, infection and even epithelial ingrowth. Not all laser corrections are spot on in every case. Should there be any residual refractive error, an enhancement (retreatment) can be done to address this.