Femtosecond Lenticule Extraction (FLEx): A New Alternative to LASIK

The Singapore National Eye Centre (SNEC) now offers patients a new alternative to conventional LASIK - Femtosecond Lenticule Extraction (FLEx) – an evolution of laser refractive surgery.

What is FLEx, and how does it differ from conventional bladeless LASIK?

LASIK involves two separate stages. Firstly, a corneal flap is made, either with a mechanical blade (microkeratome LASIK), or with a femtosecond surgical laser (bladeless LASIK). Secondly, an excimer laser is used to laser away corneal tissue to the required shape to treat the myopia, hyperopia or astigmatism, and the flap is then replaced. Nowadays, more and more patients are opting for the newer two-laser (femtosecond and excimer laser) combination treatment, i.e. bladeless LASIK.

FLEx, which stands for Femtosecond Lenticule Extraction, is a new alternative to conventional bladeless LASIK – in this procedure the entire treatment is performed with just one laser, the VisuMax Femtosecond Laser from Carl Zeiss Meditec, an advanced new generation femtosecond lasers developed for corneal surgery. Femtosecond lasers are more precise than excimer lasers, and this enables innovative laser treatments beyond the limits of excimer laser technologies. The VisuMax Laser also has significant advantages over other femtosecond lasers in that it provides a more gentle treatment which results in less discomfort during surgery (which SNEC has recently proven in clinical trials), and only uses about a quarter of the total laser energy on the cornea, as compared to other femtosecond lasers due to its laser focusing beam. As a result, FLEx treatment is only possible with this highly precise femtosecond laser – currently no other femtosecond lasers are able to perform FLEx surgery.

In FLEx surgery, the VisuMax laser is able to cut a lens-shaped layer (a lenticule) from within the cornea. The lens is simply removed either through a LASIK type flap, or can be removed through a small keyhole incision, all performed at the same sitting and with the one laser. The shape of the lenticule is accurately calculated to exactly match the patient’s degree of myopia or astigmatism, so then when it is removed, the patient should have no more myopia or astigmatism. Being a single-stage procedure, treatment time is more than halved, as compared to bladeless LASIK. Approximately over a thousand FLEx procedures have been performed to date, in Europe and Asia, and studies there suggest that FLEx provides for greater accuracy than conventional LASIK, especially for higher degrees of myopia.

FLEx - Advantages and Benefits to Patients

The advantages and benefits of FLEx to patients compared to LASIK are:

1. FLEx appears to be more accurate than LASIK for higher degrees of myopia, e.g., from 500 to 1,000 degrees
2. FLEx is faster to perform than LASIK - only one laser is used
3. A full LASIK-type corneal flap may not be necessary – in a modified procedure known as SMILE (Small Incision Lenticule Extraction).Instead of a full LASIK flap being cut and opened out, a much smaller keyhole incision is made through which the lenticule can be extracted – with a smaller wound, SMILE results in a stronger eye, less immediate postoperative discomfort and tearing and the potential for less dry eye problems as compared to LASIK. Reducing these side-effects and complications, normally associated with LASIK, may make SMILE a potentially safer option.