We now have the capability of performing a customized application of the excimer laser to attempt a more complete correction of the elements in the eye’s focusing system that produce blurry vision. This custom approach employs a device called a WaveScan. It is also referred to as wavefront-guided surgery. The concept stems from a technology called adaptive optics which was initially developed to improve the images from astronomical telescopes.
The concept of the WaveScan utilizes an instrument which passes multiple small points of light into the eye and measures the distortion after the light comes back out through all of the focusing elements of the eye. By evaluating how all of these elements have been affected by the eye’s focusing system, a customized map of the eye can be developed. This allows for the evaluation of any irregularity in the eye’s focusing system which may affect vision. In particular, it allows the identification of irregular elements beyond simple nearsightedness and astigmatism which are already correctable by standard laser treatment. The addition of the wavefront-guided technology allows for the possibility of a more accurate correction of the vision. Additionally, because of the way in which the wavefront-guided treatment is applied to the cornea, there may be a better coverage for patients with pupils that dilate to a greater extent in dim light. This therefore can improve the visual performance in low light situations. The application of a wavefront-guided treatment does not produce any significant change in the treatment time or the healing time. It does however require a pre-operative measurement of the eye using the WaveScan device.
Currently, the WaveScan technology is approved in the LASIK platform to correct up to 11 diopters of nearsightedness with up to 3 diopters of astigmatism, as well as up to 3 diopters of farsightedness with up to 2 diopters of astigmatism, and between 1 to 5 diopters of mixed astigmatism. This technology may also be used with the PRK surface treatment for the same indications although this is considered an off-label application according to FDA.
It is important to have detailed discussion regarding whether standard or custom wavefront-guided laser correction would be most appropriate for each individual patient.