FDA oks improved Tecnis toric calculator

The FDA has approved a software update to Abbott’s toric calculator that factors in posterior corneal astigmatism into lens calculation.

“By incorporating posterior corneal power and an exact vergence calculation for both toric and spherical IOL power, the new Tecnis toric IOL calculator elegantly and comprehensively addresses posterior corneal astigmatism and potential inaccuracies,” said Douglas D. Koch, MD, who helped develop the algorithm used in the calculator.

Dr. Koch and his fellow researchers at Baylor College of Medicine in Houston found that not measuring posterior corneal astigmatism could result in incorrect estimation of total corneal astigmatism, reducing the efficacy of toric IOLs by over correcting with-the-rule astigmatism and under correcting against-the-rule astigmatism.

Using data from a Galilei Scheimpflug, they found an average of about 0.5 D of posterior astigmatism when patients had with-the-rule on the front, and about 0.3 D when they had against-the-rule on the front.