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Ophthalmology. 2018 Feb;125(2):169-178. doi: 10.1016/j.ophtha.2017.08.027. Epub 2017 Sep 23.

Accuracy of Intraocular Lens Calculation Formulas.

Author information

The Permanent Medical Group, Redwood City Medical Center, Redwood City, California. Electronic address:
Department of Ophthalmology, Baylor College of Medicine, Houston, Texas.
The Permanent Medical Group, Redwood City Medical Center, Redwood City, California.



To compare the accuracy of intraocular lens (IOL) calculation formulas (Barrett Universal II, Haigis, Hoffer Q, Holladay 1, Holladay 2, Olsen, and SRK/T) in the prediction of postoperative refraction using a single optical biometry device.


Retrospective consecutive case series.


A total of 13 301 cataract operations with an AcrySof SN60WF implant and 5200 operations with a SA60AT implant (Alcon Laboratories, Inc., Fort Worth, TX).


All patients undergoing cataract surgery between July 1, 2014, and December 31, 2015, with Lenstar 900 optical biometry were eligible. A single eye per patient was included in the final analysis, resulting in a total of 18 501 cases. We compared the performance of each formula with respect to the error in predicted spherical equivalent and evaluated the effect of applying the Wang-Koch (WK) adjustment for eyes with axial length >25.0 mm on 4 of the formulas.


For the SN60WF, the standard deviation of the prediction error, in order of lowest to highest, was the Barrett Universal II (0.404), Olsen (0.424), Haigis (0.437), Holladay 2 (0.450), Holladay 1 (0.453), SRK/T (0.463), and Hoffer Q (0.473), and the results for the SA60AT were similar. The Barrett formula was significantly better than the other formulas in postoperative refraction prediction (P < 0.01) for both IOL types. Application of the WK axial length modification generally resulted in a shift from hyperopic to myopic outcomes in long eyes.


Overall, the Barrett Universal II formula had the lowest prediction error for the 2 IOL models studied.

[Indexed for MEDLINE]

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