Some beginning surgeons like to shift the phaco incision in order to maximize their “hand comfort” even if that means placing it on an oblique axis. While smaller 2.2mm incisions may induce slightly less astigmatic effect than a 2.8mm incision, it is still preferable to make this incision on the steep axis if possible. The microscope and surgeon’s chair can be shifted or moved in order to accomplish this. For most elderly cataract patients the steep corneal axis tends to be against-the-rule at close to the 180 degree meridian — good for the surgeon sitting temporal. For younger cataract patients, particularly myopic ones, the steep corneal axis tends to be with-the-rule at close to the 90 degree meridian — good for the surgeon sitting superior.
This video is a complete cataract case where the step axis is at 30 degrees which makes it very easy for a right-handed surgeon sitting temporally. Our cataract surgery patients routinely want a refractive outcome and taking into account the astigmatism is an important part of that.
click to learn about operating on the steep corneal axis: