Blog

Background

I became a believer in femtosecond flap creation in 2005. While this technology was initially made available to my practice in 2000, I elected to allow the learning curve to progress before committing myself to any surgical changes. By 2005, the IntraLase 30-kHz femtosecond laser became available with reduced flap creation time of approximately 30 seconds and advances in post-operative inflammation and visual recovery. However, my main initial attraction to the femtosecond flap creation was safety. We all know the challenges that flap complications with the microkeratome can cause both patients and surgeons, so I was very interested in a technology that would remove this challenge from the LASIK equation. Another unexpected benefit I noted with the femtosecond flap was the almost complete elimination of epithelial ingrowth and significant flap striae.

By 2007, the IntraLase 60-kHz femtosecond laser had become available, which reduced the flap creation time to approximately 20 seconds. It further improved the post-operative results with less flap edema and inflammation and delivered faster visual recovery. At this point, I could no longer justify using the microkeratome. Furthermore, we discovered that patients were very receptive to the concept of flap creation with the “laser” rather than the “blade,” which offered us a competitive advantage. For these reasons, in 2007, I elected to use the IntraLase System exclusively.

The iFS Femtosecond Laser

Since 2010, I have been privileged to use the latest iFS Laser. The iFS Laser is a 150-kHz femtosecond laser, reducing flap creation to 10-12 seconds. While any reduction in surgical time is welcomed, I think this is the least significant of the femtosecond improvements featured in the iFS System. The density of the laser pulses can now be increased to a 7x7 spot line separation compared to the 8x8 spot line separation of the 60-kHz and the 30-kHz femtosecond lasers. Clinically, this means the flaps are about 50 percent easier to lift. The reduced energy per pulse means a further reduction in flap edema and inflammation with improved visual recovery. The high-resolution, heads-up video display has proven to be very beneficial, as it allows clearer identification of the meniscus. The iFS Laser allows for an inverted side cut (I have been using it at 110 degrees for the last year) which has been shown to increase the flap stability, enhance the post-operative healing and reduce post-operative dry eye. Finally, the iFS Laser allows for the creation of oval or ellipsoid flaps as originally described by Kerry Assil, MD. This allows the flap to be customized to the oval shape of the normal cornea and the oval ablation pattern associated with astigmatism.

Faster Visual Recovery

I have been impressed with the rapid visual recovery of IntraLase Technology, and this recovery continues to advance with each evolution of the platform. The reasons for this powerful benefit are grounded in solid science. First, the flap created is planar with a uniform thickness, unlike the microkeratome, which creates a meniscus flap that is uneven. When the flap is put back in place after the excimer correction, it fits precisely because of the well-defined side cut. These two improvements reduce the incidence of microstriae.
The result? A safer procedure with quicker visual recovery (Figure 1).

Summary

After 15 years of performing LASIK, I am very pleased to witness the improvement of our results to the point that now the pre-operative BCVA has been surpassed by the post-operative UCVA. In fact, in a recent study conducted with the iFS Laser at our practice, 98.4% of our patients are 20/20 at day one. The bottom line? The iFS Laser delivers even better visual recovery than previous IntraLase lasers and microkeratomes.

Reference

1. Tanna M, Schallhorn SC, Hettinger KA. Femtosecond laser versus mechanical microkeratome: a retrospective comparison of visual outcomes at 3 months.
   Refract Surg. 2009;25(7 Suppl):S668-S671.