LEARNING FROM GIANTS' mistakes.

Learning from Giants' Mistakes in Cataract Surgery Fedorov 67 vs Fyodorov 75

​Samir I Sayegh, MD, PhD, FACS, FAAO, FASRS

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Abstract 
One of the most influential papers in the history of cataract surgery is Fedorov and Kolinko’s 1967 paper. All so called third and fourth generation intraocular lens calculation formulas implemented to this day are based on it. We show that the actual expression given in the 1967 article is incorrect and was subsequently corrected by Fedorov and colleagues in 1975.  We show the source of error and comment on implications for modern day intraocular power calculations for cataract surgery. 
Introduction 
​Slava Fedorov’s contributions to Ophthalmology are profound and lasting. In a paper with Albina Kolinko in 1967 they attempted a rational theoretical approach to the computation of intraocular lens (IOL) power based on biometry of the patient’s eye1. The paper was written in Russian and was followed by a few similar attempts by mainly European ophthalmologists.  In 1975, together with Galin and Linksz, Fedorov (Fyodorov) contributed a similar article and computation to the English literature2. This made the approach more accessible to a wider readership and was followed by the (re)introduction of regression methods exemplified by SRK3,4 and somewhat later, by a realization that theoretical methods were foundational and need be adopted albeit with a grain of tweaking! This is represented by some of the major “third generation” or “vergence based” formulas such as Holladay1, SRKT and HofferQ5,6,7, all of which cite at least one of the Fyodorov and colleague’s papers and are in turn some of the most cited and implemented papers in the IOL power calculation literature.  To our knowledge, there is no systematic comparison that has been attempted between the 1967 and 1975 versions of Fedorov and colleagues’ articles. In fact, a number of papers have cited both the 1967 and 1975 articles without mention of any discrepancy4,6,8. Others will cite only one9 or the other3,10,11.  Some will mention a date and cite the article from the other date12.  Yet others, surprisingly, cite neither13. In the present work we start by a direct comparison of the key formulas and their differences including numeric estimates and clinical implications.  We follow with an analysis of the original sources and the sources of errors and draw conclusions as to lessons to be learned.