Question: We have a Doctor that states the Barrett Universal II formula is now available on the Holladay. We have upgraded the Holladay to the newest version, but they are not showing this Barrett formula on their list of available formulas. I would like to know how to go about adding Barrett and Hill RBF formulas to HICSOAP?
Answer: 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 (included below) 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.
The Holladay Toric Calculator is the most accurate and better than the Barrett as we reported in the JCRS this year (attached in Figures 9 - 12).
You should be using the Holladay 2 formula with the Holladay Non Linear Regression option checked.