Cataract surgery has always induced astigmatism due to the incisions created during the procedure.
As we have moved to smaller and smaller incisions over the years, this effect has lessened, but it still plays an important role in our ability to deliver a predictable refractive outcome and better vision for our patients.
Astigmatism can be thought of as a vector because it has both magnitude and direction. Simple addition and subtraction are insufficient to determine the net result of our incision. We need to go back to high school trigonometry to properly add and subtract vectors. In order to