Optimal laser surgery approach to myopia correction

SMILE has represented a paradigm shift in the way surgeons use laser refractive surgery to correct the vision of patients with myopia and other conditions. DR ANTON VAN HEERDEN and MR DAVID CROPMAN discuss how it is applied in their Melbourne clinic.

Refractive laser surgery has been carried out since the early 1990s. The initial treatment PRK was followed shortly by LASIK, with the latest technology SMILE introduced just over a decade ago.

The goal of all refractive procedures is to achieve a perfect refractive outcome with the least amount of risk, side-effects and complications. We all have busy lifestyles and want a quick, safe and comfortable recovery that fits in with our daily routine.

The first and second generation laser treatments use an excimer laser to change the corneal shape thereby adjusting its refractive power. They’re both highly accurate which is why both PRK and LASIK surgeries give such remarkable results and have such an excellent track-record.

With PRK (photorefractive keratectomy), the epithelium is removed prior to the treatment. This creates a longer visual recovery (taking about a month to settle) and the eyes are very uncomfortable for the first few days. However, PRK gives excellent long-term results and is still an excellent surgical option for patients with irregular or thin corneas.

With LASIK (laser-assisted in situ keratomileusis), a flap is created with a femtosecond laser. The flap is folded back prior to the excimer laser treatment. This surgery is pain-free with a quick recovery which is why it’s been the most popular laser treatment for two decades. However, the big drawback is the flap which permanently remains a weaker part of the eye and is therefore at risk of being dislodged by trauma. Because of this risk, patients with active lifestyles and professional sportsmen often opted for PRK over LASIK.

The paradigm shift in laser surgery came in 2014 with the introduction of SMILE (Small Incision Lenticule Extraction). Using the Zeiss VISUMAX femtosecond laser, a lenticule is created within the cornea. This is then removed manually, reshaping the cornea and adjusting its refractive power.

SMILE has seen exponential growth over the past decade with more than six million eyes treated globally. The increasing popularity of this technology is due to its precise results, improved biomechanics stability and reduction in dry eyes due to an improved ocular surface. I’ve made it a go-to procedure to correct myopic eyes that are no longer progressing.

Advantages of SMILE:

1. It produces safe predictable refractive outcomes¹
2. There are less dry eyes than with LASIK²
3. It’s a flap-free procedure meaning there is no risk of future flap dislocation
4. It creates a more stable refraction with a lower risk of regression³
5. Patients can safely return to all activities after three days.

Our experience 

Eye Laser Specialists, a practice I operate in Melbourne, has offered SMILE surgery since January 2020 performing over 1,400 safe treatments with excellent outcomes.

The learning curve: SMILE surgery is technically more challenging than both LASIK and PRK surgery. Although the learning curve is initially steep, the surgical outcomes are excellent from the start.

The patient experience: Bilateral SMILE surgery is quickly carried out by a femtosecond laser in less than 15 minutes. Though the majority of patients don’t elect to have a mild sedative, we do offer one.

The whole treatment is carried out with a single laser. Firstly, a lenticule is created in under 30 seconds and this is carefully removed through a key- hole incision. The procedure is painless and well tolerated. The VISUMAX has a curved interface which means less suction pressure and a more comfortable laser experience.

For the initial four hours post-surgery, the eyes are slightly gritty with mild photophobia yet oral analgesics are rarely required. The majority of patients achieve 6/6 or better the day after surgery and return to work within a couple of days of their treatment.

Refractive outcomes: Independent analysis of our results shows that 94% of our patients are with less than 0.50 diopters of sphere three months after surgery. Astigmatism correction is excellent with 90% patients <0.50 diopters of astigmatism three months after surgery.

Re-treatments: We have performed enhancements on five eyes post SMILE surgery (0.008% of patients): four of these were treated with thin- flap LASIK and one patient with PRK. All of these patients have had an excellent outcome. This is far less than the 2% of enhancements required post LASIK surgery.