LASIK or Refractive Laser Surgery is certainly one of the most fascinating procedures in modern medicine. It is of the most accurate and successful surgeries performed in the world. But with good results comes great expectation! Advances in technology within laser refractive surgery are generally aimed at improving the predictability of the procedure. Improvements include:
The laser:
The laser used in LASIK surgery is an Excimer laser. This laser can
remove as little as 0.25 micrometers of the cornea at a time, making it
extremely accurate. The initial broad beam lasers are generally replaced
these days with slit scanning or spot scanning laser beams. These
lasers give a smoother laser surface and make wavefront correction
possible.
Wavefront:
Wavefront aberrations are abnormalities in the focus system of the eye
that cannot be corrected with spectacles. It is also referred to as
'Higher Order Aberrations'. Correcting these higher order aberrations can
improve the quality of vision in certain patients. To detect the
wavefront abnormalities, special equipment are used to create a customised map(see image on right) of each eye. This information is then used to adjust the laser specifically for each eye.
Eye Tracking:
To enable an accurate laser ablation, all modern refractive lasers have
an eye tracking system. These systems identify an area of the iris or
pupil and will adjust to tiny eye movements during surgery. If any big
movements occur, the laser will stop automatically and resume treatment
as soon as the eye has been aligned again. (see image on right)
Cutting the Flap:
Cutting the corneal flap during LASIK surgery is one of the most crucial
steps during the procedure. Exact depth and size is most important and
will impact a great deal on the final result. These days this step can
either be done with Femtosecond Laser or modern Microkeratomes. Both
of these systems give equal visual results with a very good safety and
accuracy profile.
The Surgeon:
Although technology helps us a lot to make LASIK surgery safer and more
predictable, the skill of the surgeon cannot be left out of the
equation. Staying in touch with technology as well as understanding and
mastering the “art” of refractive surgery by the individual surgeon will
always carry most of the weight in determining the outcome of the
surgery.