Laser Vision Correction: 5 Things to Know About ReLEx® SMILE®

When we look at technology’s impact on healthcare, artificial intelligence and medical robots get much of the attention. But other technologies are contributing their fair share toward improving healthcare; laser technology has witnessed a number of significant advances in recent years, leading to safer, less invasive and more effective medical treatments.

Case in point: minimally-invasive laser vision correction surgery. The new laser technology used in the procedure known as ReLEx® SMILE® — an acronym for refractive lenticule extraction and small incision lenticule extraction — represents perhaps the most significant advance in cornea refractive surgery since the introduction of LASIK more than 20 years ago.

Cornea refractive surgery permanently changes the curvature of the cornea to better focus light onto the retina. It is a treatment option for four vision-related conditions involving refractive errors:
  • Myopia (nearsightedness) is a condition where up close objects can be seen clearly, but objects further away are usually blurry, as the focus point of light is in front of the retina instead of on it. Myopia may also be caused by the cornea having too much curvature for the eyeball length.
  • Hyperopia (farsightedness) causes people to see distant objects more clearly than close-up objects, typically due to a shorter eyeball length which focuses light behind the retina.
  • Astigmatism is a condition in which the shape of the cornea is abnormal or uneven, preventing the eye from focusing light evenly onto the retina. In an eye with astigmatism, the cornea is curved unevenly in areas, which can be more rounded or steeper than other areas. Images tend to appear blurry and stretched.
  • Presbyopia is the gradual loss of the eyes’ ability to see clearly at close distance. The condition typically affects people beginning around the age of 40. It is fairly common for people to have both presbyopia and another refractive error at the same time.

LASIK remains the world’s most popular refractive surgery — the procedure has been performed on more than 35 million patients and can treat myopia, hyperopia, and astigmatism. LASIK cannot treat the presbyopia condition because presbyopia is a result of less eye muscle strength to move the lens to see near clearly and from less lens flexibility.

Surgeons can correct the dominant eye for far vision and the non-dominant eye for near vision, known as the Monovision technique. ReLEx® SMILE® can do this technique too if you are shortsighted and have astigmatism. Before choosing Monovision, you need to try contact lenses to see how Monovision feels.

ReLEx® SMILE® — which currently offers treatments for myopia and astigmatism — offers distinct advantages that can make it a better choice for some patients. If you are considering cornea refraction surgery, here are five things to know about ReLEx® SMILE®.

1. No flap is cut: The biggest difference between ReLEx® SMILE® and LASIK is that only LASIK involves the cutting of a corneal flap.LASIK uses a microkeratome (blade) or Femtosecond laser to cut a small flap in the cornea which is folded back while an excimer laser ablates and reshapes the cornea to correct refractive errors. After the ablation, the corneal flap is laid back down and left to heal in place.
No flap is cut during ReLEx® SMILE®, so there are no flap-related complications. The integrity of the cornea is more preserved, and the lenticule is removed mechanically through a tiny incision (2 to 4 mm). That means there is less cutting of corneal nerves during ReLEx® SMILE®, thereby reducing the post-operative dry eyes. ReLEx® SMILE® is often preferred by athletes and those involved in contact sports, since there is no risk of flap displacement, which is possible for patients who have undergone LASIK corrective surgery.

2. The incision is much smaller: The ReLEx® SMILE® incision is 80% smaller. The incision used in LASIK is typically about 20 mm. For ReLEx® SMILE®, the incision is about 4 mm or less. A 4-mm incision typically heals faster than a 20-mm incision, which can translate to less eye irritation, a quicker return to normal activities — typically in about one week for most types of exercise and sports — and lower risk of wound-related infections or other complications.

3. It treats shortsightedness and astigmatism: ReLEx® SMILE® is most effective for adult patients with shortsightedness (myopia) in the range of -0.50 Diopters to -10 Diopters (low to high shortsightedness) and those with cylinder astigmatism (0 to 5.0 Diopters); it is not currently used for treating farsightedness (hyperopia).

4. The procedure takes 30 minutes: Like LASIK, the ReLEx® SMILE® procedure takes about 30 minutes. Patients are awake and lie on their back during the procedure. A topical anesthesia in eye-drop form is applied to the eyes prior to the procedure, but there are no injections involved. Patients also receive pain-relief medication and a tranquilizer to relax.

5. FYI: Before and after: Prior to the procedure, contact lens wearers will need to stop wearing their lenses for at least a few days to allow the cornea to return to its normal curvature. Almost immediately after the procedure concludes, patients are able to see big things, but vision will be somewhat foggy. For the first day, patients should relax, lie on their back, close their eyes and sleep if possible, to promote faster wound healing. The next day, patients return for a follow-up with the doctor to monitor healing and vision progress. Further follow-ups are done after 1 week and 1, 3 and 6 months.
If you are considering cornea refraction surgery, it is important to talk to your doctor to determine whether you are a good candidate for the procedure, and to understand the benefits, risks and potential complications of each of the available options. This will ensure you make a fully informed decision that provides the best possible outcome for your unique individual situation.

By Dr. Tharinee Kulkamthorn, Cornea and Refractive Surgery specialist, The Eye Center, Bumrungrad International Hospital
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