Laser in situ keratomileusis (LASIK) is the most common refractive surgical procedure in the United States today. This procedure involves cutting a thin flap in the cornea either with a fine blade (microkeratome) or a femtosecond laser (so-called bladeless method) in order to expose the stromal bed.1–4 Femtosecond laser systems have successfully entered the refractive surgery market, primarily due to their enhanced precision and minimized collateral tissue effects.5–10 Diode pumped all-solid-state femtosecond lasers are now also commonly used or being investigated to perform additional procedures, such as corneal transplants and fs-lentotomy.11–15 The improvement of the technology resulted in a progressive increase of the repetition emission frequency up to 60 and 150 kHz or even higher repetition rates.16–18 One of the most popular commercial systems is the 60 kHz FS 60 Laser (AMO Inc., Santa Ana, CA). However, the higher repetition rate will increase the average laser power reaching both the retina and iris during LASIK surgery, raising the potential risk of thermal damage. Preliminary estimates suggest that almost half of laser energy passes beyond the cornea with potential effects on the retina and iris.19–21 The temperature increase in human cadaver retina was investigated via ex vivo experiments and simulation by our group previously.19 To study the temperature increase of the iris is also reasonable, since during the LASIK surgery the iris is closer to the focus of the laser beam than the retina. Although the iris does not absorb laser energy as strongly as the retina does, it is also pigmented and absorbs the laser energy. In order to model the laser exposure of the iris during femtosecond laser corneal surgery, we have developed a two-dimensional computer simulation using the COMSOL finite element software (Comsol Inc., Burlington, MA). To validate our simulation results ex vivo experiments were performed using porcine cadaver iris where the temperature increase was measured by an infrared thermal camera. Different laser energies were used for both the simulation and the ex vivo experiments. The temperature of the samples was simulated and measured at every second throughout the 24 second long flap procedure. As the extension of the model, we also simulated the situation for other femtosecond laser systems, namely the 150 kHz iFS Advanced Femtosecond Laser (AMO Inc., Santa Ana, CA), the FEMTEC system (Technolas Perfect Vision Inc., Heidelberg, Germany), and the VisuMax system (Carl Zeiss Inc., Jena, Germany).