To the Editor I read with great interest the recent article by Ladas et al1 and the accompanying Invited Commentary by Hee.2 Hee states, “Despite these technological advances, the preoperative calculation of optimal postoperative IOL [intraocular lens] power has remained essentially unchanged during the past 20 years.”2 This might mean little has happened in IOL power formula development since 1995. This statement does not seem to consider the work done by Thomas Olsen, MD, PhD, Graham D. Barrett, FRACO, FRACS, Wolfgang Haigis, PhD, and many others. In referencing the article on the Hoffer Q formula, the crucial errata are missing.3 Hee also states, “The Haigis formula adds a third variable—preoperative anterior chamber depth.”2 It does not add a third variable; it replaces the corneal power (K) with the preoperative anterior chamber depth and thus uses only 2 variables, not 3.
Hoffer KJ. Origin of Multiple Formula Use to Calculate Intraocular Lens Power. JAMA Ophthalmol. 2016;134(7):847-848. doi:10.1001/jamaophthalmol.2016.1043