What is Wavefront LASIK ?
Wavefront LASIK is the latest generation technology used to treat refractive visual errors, as used for example with Technolas Perfect Vision’s ZYOPTIX.® Platform. It provides the most technologically advanced measurement of your optical system, enabling the laser eye surgeon to plan a treatment that exactly matches individual vision errors.
Wavefront technology is based on the principle that if an eye has no imperfections, light passing through it would not scatter. But as no eye is perfect, light scatters to form a distinct pattern- called a Wavefront. This Wavefront map is then used diagnostically for pre-operative screening and post-surgical analysis. The Aberrometer for instance the Technolas Perfect Vision Zywave, measures the eye from the centre to the outer edges of the pupil. This is very important as at night your pupils open up and more light is scattered in the periphery.Your eye surgeon needs to know equally as much about your day time vision as your night time.
What is the advantage of Wavefront technology?
The Wavefront LASIK treatment process
A laser eye surgeon or optical technician uses the aberrometer to generate your Wavefront map. Software then converts the map into an individualised treatment profile based on the information collected to treat your prescription. This information is then transferred electronically to the computer controlling the laser which then calculates the shot pattern.The eye surgeon then utilises this information to perform your actual procedure by accurately placing, with the aid of the eye tracker, the laser pulses at the correct position on the cornea.
Due to the angle of incidence the light of the laser beam is ovalized increasingly towards the periphery and becomes partially reflected which results in less fluence and thus sub-optimal ablation. Wavefront Optimized laser systems place more pulses in the peripheral area to compensate for energy loss and reflections. This provides a nearly 100% optical zone and a minimized transition zone. At the same time, the natural aspheric shape of the cornea is preserved and the induction of spherical aberrations minimized. In non-wavefront optimized treatments the decreasing fluence and reflections are not compensated and the ablation depth in the peripheral area is insufficient. As a result, the transition between the optical zone and the transition zone is less smooth, while the transition zone itself is fairly large. The non-aspheric ablation profile alters the natural corneal shape and induces spherical aberrations.
A Wavefront study
Wavefront-guided LASIK corrects higher-order optical distortions and provides significantly improved contrast sensitivity compared with standard LASIK, according to a study in the March issue of Ophthalmology. In this comparative study conducted in Israel, 24 eyes of 13 patients were treated with wavefront-guided LASIK and 22 eyes of 12 patients were treated with standard LASIK. At one month after surgery, it was found that 88% of the contrast sensitivity measurements improved in the wavefront group, whereas only 40% improved in the standard group. Also, uncorrected visual acuity of 20/20 or better was achieved by 72% of the wavefront group and by 70% of the standard group.