Range treatable: Glasses prescription: +4.00 to -9.00 D and up to 4.00 D astigmatism. Every year, close to 100,000 Femto-LASIK procedures are performed in the UK, and many millions of treatments have been performed worldwide since the introduction of LASIK in the 1990s.
In modern Femto-LASIK surgery we use two lasers: a femtosecond laser (Intralase), which is used to create a hinged flap of surface corneal tissue about 1/10 of a millimetre thick. The flap is then lifted and folded back. With the second laser, a computer controlled wavefront excimer laser, the corneal surface beneath is reshaped. At the end of the procedure the corneal flap is folded back into place. In essence, the cornea is reshaped without surface damage/removal.
Continued efforts at increasing safety in LASIK have led to the development of the Intralase femtosecond laser.
Concentrating laser energy within a very short pulse duration (a femtosecond is 1/100,000th of a second), the femtosecond laser allows the creation of a microscopic gas bubble in the target tissues. A rapid burst of closely spaced femtosecond laser pulses is scanned through the cornea by the Intralase laser, separating the target tissues by joining a 3D pattern of microscopic gas bubbles together to create a LASIK flap quickly, painlessly and accurately.
Femtolaser LASIK flaps are surgeons’ and patients’ preferred choice because of their precision, reproducibility and elimination of blade-related complications. LASIK Flap complications can still occur in Intralase Femto-LASIK, but they can usually be treated without affecting the visual result. The greatest advantage of Femto-LASIK is its quick visual recovery and minimal discomfort after surgery, along excellent visual results.
How does Femto-LASIK work
Refractive surgery in general works by changing the corneal shape and building the spectacles correction inside the cornea .
- Myopia: Laser surgery removes tissue form the central cornea thus flattening the corneal curvature so that your eye’s focusing power is reduced. Images that are focused in front of your retina as a result of a longer eye or steep corneal curve, are pushed closer to (or directly onto) the retina after surgery.
- Hyperopia: refractive surgery procedures work to establish a steeper cornea to increase your eye’s focusing power. Images that are focused beyond the retina, because of a short eye or flat cornea, will be pulled closer to (or directly onto) the retina following surgery.
- Astigmatism: again the cornea is flattened only in the steeper corneal meridian to be made more symmetrical. The result of this procedure is that images focus clearly on the retina rather than being distorted from light scattering through an abnormally-shaped cornea.
The Femto-LASIK procedure
- Step 1: The eye is anesthetized with topical eye drops
- Step 2: A corneal flap is created but the Femto-LASIK laser on the outer layer of the eye. It is cut and flipped open
- Step 3: The excimer wavefront laser is used to reshape the cornea
- Step 4: The Femto-LASIK corneal flap is then folded back in place