With-the-rule (WTR) astigmatism is where the steep axis is at or near the 90 degree axis. Placing incisions on the steep axis can help reduce the astigmatism at the time of cataract surgery. Many cataract surgeons, particularly in the USA, like to use temporal incisions for cataract surgery because the temporal limbus is farther from the visual axis and most cataract patients tend to have the steep axis of astigmatism at or near the 180 degree axis (ATR or against-the-rule).
Operating when sitting temporally offers better ergonomics with easier access in patients with deep set eyes or prominent brows. In the case shown here, the patient had a steep axis of about 75 degrees but I still wanted to sit in the temporal position. The solution is to adjust or rotate the speculum and the microscope so that the incision can be made on this steep axis. At the end of the case, we pair this with an additional incision to help reduce astigmatism even more.
Click below to learn how to adjust your seating position to benefit the patient: