HICSOAP does not use or support the Barrett formula. The BARRETT Universal Formula is proprietary and we do not have it in the IOL Consultant Software. Koch first found this and reported the Wang/Koch adjustment and we then published the Non-Linear Long Eye Adjustment in 2018. The recent article by Melles and Holladay in Ophthalmology shows a difference in the Holladay 2 and the Barrett in LONG EYES. The article explains that the H1 and H2 formulas are less accurate in long eyes because the optical axial length measurement is wrong. In the latest version of the IOL Consultant we have added a Holladay Non Linear Regression which is superior to the WANG/Koch and any other formula.

In the Study with Melles (Melles RB, MD, Holladay JT, Chang WJ. Accuracy of Intraocular Lens Calculation Formulas. Ophthalmology 2018 Feb;125(2):169-178) we found that if you use the Holladay Non Linear Regression in Long Eyes and used the REFRACTION before affected by the cataract (if not know leave blank) the results were 80% within +/- 0.50 D.

The Holladay Toric Calculator is the most accurate and better than the Barrett as we reported in the JCRS.

You should be using the Holladay 2 formula with the Holladay Non-Linear Regression option checked.