Measuring Surgically Induced Astigmatism Using Corneal Total Corneal Wavefront.

To evaluate surgically induced astigmatism in cataract surgery using pre-and post-operatively measured corneal wavefront

The study included results from two private eye clinics situated in Haugesund and Stavanger in Norway

This was a retrospective study of successful cataract or refractive lens surgery. Main incision was 2.2mm@100 deg. Patients were measured preoperatively and 2-4 months postoperatively with an OCT based biometer (Anterion .Heidelberg Engineering). Surgically induced astigmatism (SIA) was calculated as the vector difference of postoperative minus preoperative measured corneal astigmatism. SIA was calculated from Anterior axial corneal astigmatism at 3mm ring (SIA AntAx), total corneal astigmatism at 3mm ring (SIA TCP) and total corneal wavefront astigmatism at 4mm pupil zone (SIA WF). The WF astigmatism was converted from Zernike coefficients (microns) of oblique and with-the-rule/against-the-rule astigmatism to diopters of cylinder and axis.

110 eyes of 110 patiens were included in the study. Mean age was 58.7 years, 43% were female. Mean Follow-up time was 99 days. Mean postoperative spherical equivalent was -0.10 D, and mean cylinder was -0,3 D The measured induce astigmatism was 0.17 D @ 3, 0.07 D @17, and 0.06 D @16 for SIA WF, SIA AntAx and SIA Tcp. Only SIA WF and SIA AntAx was significantly different from zero.