Iris Registration is an amazing development by VISX available with customized treatments. Surgeons measure the eye while the patient is sitting up in an examination chair. When a patient lies down, it is common for the eyes to rotate a few degrees clockwise or counterclockwise. Without iris registration, surgeons have to mark the eye with a pen at the 3 o'clock and 9 o'clock positions. When the patient lies down, the surgeon would visually check to see if these spots had moved. If they had, the surgeon would adjust the head position to move the spots roughly into the proper alignment. In this way, treatments ended up being out of proper alignment.

With Iris Registration, hallmarks of the iris (the colored part of the eye) are scanned into the computer while the patient is sitting up. When the patient lies down under the laser, the computer tracking system locates these hallmarks to determine how many degrees the eye has rotated. The exact amount of rotation is reported to the surgeon for verification. The surgeon can then rotate the laser treatment the same amount to achieve the most precise alignment and precision. Though this technology is important for everyone considering LASIK, it is critical for patients with higher levels of astigmatism.