Fuchs' endothelial dystrophy is a progressive, bilateral disease of the corneal endothelium, which eventually leads to corneal decompensation. In the early stage, some patients develop visually significant cataract. During cataract surgery ultrasound (US) power is used to emulsify the lens, which leads to endothelial cell loss and tissue damage. The reduction of US power has become the primary surgical goal in cataract surgery, which is especially important in patients with Fuchs' endothelial dystrophy to limit endothelial cell loss.