New Regression Formula for Toric IOL Calculations

About 4 years ago, Douglas D. Koch, MD, taught us the importance of including posterior corneal curvature in the presurgical calculations for astigmatic correction. But how can we actually do it?

On Sunday at AAO 2016, Adi Abulafia, MD, presented a new regression formula that he developed with Dr. Koch to calculate the estimated total corneal astigmatism based on standard keratometry measurements. In a retrospective case series, Dr. Abulafia compared the accuracy of 2 toric IOL calculators with or without a new regression formula. He found that the Alcon and the Holladay toric calculators had a higher proportion of eyes within ±0.50 D of the predicted residual astigmatism with the Abulafia-Koch formula (76.9% and 78.2%, respectively) than without it (both 30.8%).

“The nice thing about it is it can be used with any standard toric IOL calculator,” Dr. Abulafia said.

The formula was published in the May 2016 issue of the Journal of Cataract & Refractive Surgery. —Susanne Medeiros

Financial disclosures. Dr. Abulafia: Haag-Streit: C; PhysIOL: C.

Disclosure key. C = Consultant/Advisor; E = Employee; L = Speakers bureau; O = Equity owner; P = Patents/Royalty; S = Grant support.