The aim of this study was to compare the visual and refractive outcomes of total keratometry (TK) versus anterior keratometry (AK) measurements of the IOLMaster 700® (Carl Zeiss Meditec AG, Jena, Germany) in surgery for age-related cataract with preexisting corneal astigmatism.
Monocentric retrospective comparative study. The IOLMaster 700® biometer was used in the 2 groups: in AK mode (AK group) and in TK mode (TK group), for toric IOL (AT TORBI 709 MP) calculation with ZCALC®, Zeiss toric IOL calculator. A 2:1 matching was made between the AK and TK groups. Uncorrected distance visual acuity (UDVA), the correction index and the error in predicted residual astigmatism were analyzed 1 month postoperatively using the vector analysis by the Alpins method.
The whole cohort included 405 eyes distributed as follows after 2:1 matching: 158 eyes in the AK group and 79 eyes in the TK group. The mean UDVA was similar in both groups (0.07 ± 0.10 LogMAR; p = 0.587). No significant difference in mean absolute error in predicted residual astigmatism (0.37 ± 0.33 D versus 0.35 ± 0.26 D; p = 0.545) and in mean centroid error in predicted residual astigmatism (0.19 ± 0.49 at 3° and 0.06 ± 0.46 at 0°; p = 0.008 and 0.161 respectively for the x- and y-components) was found between the AK and TK groups.
TK of the IOLMaster 700® gives excellent refractive and visual outcomes, comparable to those obtained in AK mode, without showing its superiority for corneas with regular astigmatism.