In general, low suction LASIK femtosecond lasers have a lower tendency to cause blood clots on the white of eye. But they also have a higher chance of having suction loss which may complicate the surgery and even cause the abandonment of treatment and conversion to other treatment methods such as surface ablation techniques. These comparisons were proven by research done at the Singapore National Eye Centre a few years ago.
Having said that, the blood clots are generally superficial and rarely persist after a week or two.
To reduce the risk of having these blood clots, patients are advised to try and keep their eyes still during the suction phase of the femtosecond lasering. Looking straight at the target light of the laser and keeping a cool head throughout, and helping your surgeon by listening to and following instructions during the procedure will definitely contribute to a good result.