[Analyzing and tracking preoperative and intraoperative astigmatism].

Precise evaluation of preoperative astigmatism is the first step optimizing outcomes. This begins with office-based evaluation of astigmatism; corneal astigmatism is evaluated by keratometry, traditionally by Javal keratometry, but now including topography, whether Placido- or elevation-based, which allows for detailed analysis of even irregular astigmatism, including the corneal periphery, which is invaluable. Aberrometers, essentially "super-auto refractors", allow the incorporation of additional data into the qualitative analysis of astigmatism. The correlation between these multiple preoperative data helps to differentiate between corneal and total astigmatism, to infer the lenticular astigmatism, and to integrate all of these data into the clinical decision-making process. Immediately preoperatively, the 0 and 180° axes are marked; then, with the aid of a special marker, the axis of alignment for the toric IOL is also marked. Once the cataract is removed, the toric IOL is injected and pre-aligned; the viscoelastic is carefully removed, particularly from between the IOL and posterior capsule, with the toric IOL being definitively aligned at this point. These alignment techniques represent a major advance, soon to be indispensible for toric IOL surgery, which will certainly continue to grow in the future.