Software for calculating an astigmatism treatment is operable upon execution to perform the following steps: receiving an initial primary incision position； determining a power and orientation for a toric intraocular lens (IOL) to treat an astigmatism of an eye based on the initial primary incision position； determining an adjusted primary incision position based on the power and the orientation for the toric IOL to further reduce the astigmatism； and generating an output comprising the adjusted primary incision position.用於計算一散光治療之軟體在執行時可操作以進行以下步驟：接收一初始主切口位置；判定一環面眼內晶狀體(IOL)之一功率及定向以基於該初始主切口位置治療一眼睛之一散光；基於該環面IOL之該功率及該定向判定一調整之主切口位置以進一步減小該散光；及產生包括該調整之主切口位置之一輸出。
