Although most types of laser eye surgery use an excimer laser, certain patients may be better off with other types of lasers. Listed below are just a few types of lasers which can be used in vision correction surgery;
Slit scanning lasers – This type of laser uses a small beam which are linked to a rotational device with slit holes which enlarge. During surgery these laser beams scan across the holes and produce a gradually enlarging zone of ablation. This kind of laser provides a uniform beam and has the potential to produce a smoother ablation than broad-beam lasers. There are a few disadvantages such as a slightly increased risk of decentration or over correction if the laser isn’t used in conjunction with an eye tracking machine.
Spot scanning lasers – Spot scanning lasers are amongst the most commonly used type of surgical lasers and use beams with small diameters which can be scanned across the corneal area to produce the ablation zone. This method has the potential to produce very smooth reshaping and can treat irregular astigmatism better.
Eye Tracking – The majority of modern excimer lasers are used in conjunction with an automatic eye tracking system which keeps the laser beam on target. Research has consistently shown that the use of eye trackers produces better outcomes and can decrease the risk of complications when compared to lasers without such systems.
Wavefront guided – Wavefront technology has grown in popularity in recent years and now many excimer lasers are connected to a machine which can map out the eye and detect any problems in the optical system. The data is based on how light travels through your eyes and can be used to design a custom LASIK procedure for an individual. Spot scanning and slit scanning laser can both be used in conjunction with wavefront technology for guided treatments.
Patient comfort – Recent studies have found increasing amounts of evidence which indicates that the place where laser energy is applied to reshape the eye during the LASIK process, could be too small to be used effectively on larger pupil sizes. If the pupil expands (in dim light) beyond the zone where the eye was reshaped during vision correction, this may cause problems like glaring, halos and difficulty seeing at night. Therefore, some surgeons believe that the area of the zone where the laser energy is applied, should be at least as large as the patients pupil in dim light. The time it takes to reshape (ablate) your eye can also differ amongst lasers. The usual range for ablation speed is between 30 to 60 seconds and this can be important to a patients comfort as they undergo the procedure.