Laser Eye Surgery Technology

Iris Recognition / Registration

In order to gain the greatest advantage from wavefront technology it is important to be able to apply the laser treatment very precisely to specific parts of the cornea via iris recognition tracking. Tracking systems have become increasingly sophisticated over the last few years and allow the laser to follow the tiniest eye movements during surgery.

The Abbott – AMO (VISX) STAR S4® Excimer Laser

The Abbott – AMO (VISX) STAR S4® Excimer Laser


The Abbott – AMO (VISX) STAR S4® Excimer Laser uses ActiveTrak 3-D Active Eye Tracking. This is the first FDA-approved tracking system in the industry to track eye movements along the X, Y and Z axes. Therefore these features improve the accuracy of the procedure and safety for the patient. WaveScan WaveFront data creates a 3D map at the scanning process providing detailed information of the patient’s vision correction requirements.

It is also possible to photograph the unique patterns in the iris, which are as individual as fingerprints. For example, the TPV Z100 laser identifies approximately 3,000 different features of the iris and aligns exactly with these patterns so that the treatment is delivered to precisely the right areas of the cornea. The system operates while the laser is running and even compensates for rotation of the eye (dynamic rotational eye-tracking) – very important when treating astigmatism, for example.

Wavefront Technology

The human eye is an extremely powerful focusing system which, because of this high power, is often characterised by numerous optical irregularities and defects in addition to any refractive error (i.e. short sight, long sight or astigmatism). These extra optical distortions are known as higher-order aberrations and they can affect the overall quality of the final image on the retina. On average, higher-order aberrations account for around 5% of the eye’s total refractive error – in other words, 5% of the blurring of vision that we experience when not wearing spectacles. Wavefront technology is now the gold standard applied to laser eye surgery treatments and is an integral part of the treatments offered by David Gartry.

Since glasses and contact lenses cannot correct the aberrations shown by Wavefront technology patients undergoing wavefront-guided customised IntraLASIK can in theory therefore achieve better vision than they have ever had before. Wavefront-guided customised IntraLASIK is the nearest we have at the present time to the perfect laser eye treatment.


A customised treatment

Wavefront technology was originally developed by physicists and astronomers to improve images of distant stars captured by powerful lenses, such as the Hubble Telescope. In the same way, wavefront analysis provides highly detailed measurements of the optics of the human eye. When this information is programmed into the latest laser systems with advanced tracking facilities with iris recognition or iris registration, it is possible, in theory, to reproduce the perfect corneal shape to cancel out any higher-order aberrations.