If you’ve looked into laser eye surgery, it’s likely you’ve come across both SMILE eye surgery and LASIK eye surgery. Though the aim of both forms of laser eye surgery is the same – to give you freedom from reliance on glasses and contact lenses – the ways in which they achieve this are distinctly different. Keep reading to find out the differences between SMILE vs LASIK.
SMILE vs LASIK: the Procedure
SMILE and LASIK eye surgery are both types of corneal refractive surgical procedures. This means that they’re based on reshaping the cornea at the front surface of the eye in order to correct your prescription. Another corneal refractive operation is PRK. There are also techniques of refractive surgery that don’t involve modifying the corneal curvature, such as intraocular contact lenses (ICL) or refractive lens exchange (RLE).
The cornea bends light as it enters the eyeball. For sharp sight, we need light to be focused right on the retina. However, in:
- Short-sightedness (myopia), light focuses in front of the retina
- Long-sightedness (hyperopia), light focuses behind the retina
- Astigmatism, light focuses at two separate points, one or neither of which might fall on the retina
By changing the curvature of the cornea, laser procedures such as LASIK and SMILE eye surgery can correct the way light focuses through this surface so that it comes to a clear point on the retina.
LASIK Eye Surgery
LASIK eye surgery was first used for sight correction in Australia in the mid-1990s. It stands for laser-assisted in situ keratomileusis. Prior to undergoing the operation, your surgeon will perform a comprehensive examination to ensure that LASIK is the right option for you.
During these initial consultations, you’ll also have precise biometric measurements taken of your eyes to guide the laser tool for your operation. LASIK eye surgery can be appropriate for treating myopia, hyperopia, and astigmatism.
On the day of your procedure, you’ll have your eyes numbed with topical anaesthetic eyedrops. Once you’re comfortable, a section of outermost corneal tissue is cut into a hinged flap, which is opened to the side. The formation of the flap can either be performed with a manual-bladed instrument called a microkeratome or, more commonly nowadays, a femtosecond laser tool.
Once the flap has been placed out of the way, an excimer laser is applied to the deeper corneal layers in a process called photoablation. Photoablation is the selective removal of sections of tissue to adjust the corneal curvature. The amount and location of tissue removed are controlled by a computer algorithm based on your biometric measurements. Once this step is complete, the corneal flap is replaced. This flap typically self-seals over time without requiring stitches.
SMILE Eye Surgery
SMILE eye surgery is the newest form of laser sight correction. An acronym for small incision lenticule extraction, it has been promoted as a minimally invasive procedure and manages to avoid some of the potential risks that come with LASIK. At the moment, SMILE eye surgery is suitable only for myopia and astigmatism.
Similar to LASIK eye surgery, you will need to undergo a comprehensive initial examination to assess your suitability and obtain the relevant measurements. SMILE eye surgery is performed under topical anaesthetic, like LASIK. However, here is where the similarities between these two procedures end. Instead of disrupting the outer cornea by creating a flap, the femtosecond laser used for SMILE eye surgery can pass through these tissues to reach the deeper layers. The laser forms a sliver of tissue that can be extracted from the cornea through a keyhole incision. By removing this disc, or lenticule, the overall corneal curvature is reshaped with minimal disturbance.
SMILE vs LASIK: Results
Studies have found that the long-term final visual and safety outcomes between SMILE and LASIK eye surgery are largely comparable. A number of separate clinical trials have been conducted to investigate the results of SMILE vs LASIK. Their reports include:
- One small trial in the USA noted very slightly better rates of being able to achieve 6/6 (or 20/20) sight with LASIK over SMILE when assessed at one, three, six, and 12 months post-operation
- Another trial conducted in China found that SMILE demonstrated better safety and objective visual quality over LASIK but was slightly less predictable with prescriptions over -10 dioptres of myopia
- Another trial out of China reported that slightly more people undergoing SMILE achieved 6/6 sight or better compared to LASIK at six months post-op in patients with prescriptions between -8 and -10D of myopia
- Yet other clinical studies have found that those undergoing LASIK enjoyed better sight in the first week after their procedure compared to SMILE, but at one-month post-op, there was no difference between the two groups.
SMILE vs LASIK: Recovery
Between the two laser eye surgeries, LASIK tends to have a faster visual recovery with better sight on the day after your operation. However, SMILE is associated with a slightly faster overall recovery as it is less invasive. This means people undergoing SMILE are usually able to return to their normal activities, whereas those who have had LASIK will need to wait a little longer before resuming activities such as contact sports or occupations with a risk of facial trauma.
Due to the nature of the procedure, LASIK carries the risk of flap-related complications or post-operative dry eye. Conversely, being a minimally invasive procedure, SMILE surgery retains better stability of the cornea post-operation with no flap-related risks and disrupts fewer corneal nerves that might induce dry eye.
If you’re interested in laser eye surgery, speak to your ophthalmologist about whether SMILE or LASIK might be better suited for you, your prescription, and your lifestyle. Call us now on 03 9000 0389 for a consultation.
Note: Any surgical or invasive procedure carries risks. Before proceeding, you should seek a second opinion from an appropriately qualified health practitioner.
References
The Current State of SMILE vs LASIK
https://www.reviewofophthalmology.com/article/the-current-state-of-smile-vs-lasik
LASIK vs SMILE Eye Surgery
https://www.visioncenter.org/blog/lasik-vs-smile/
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