A 3-D super surface combining modern intraocular lens formulas to generate a super formula and maximize accuracy

John G. Ladas, Aazim A. Siddiqui, Uday Devgan, Albert S. Jun

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


Importance Cataract surgery is the most common eye surgery. Calculating the most accurate power of the intraocular lens (IOL) is a critical factor in optimizing patient outcomes. OBJECTIVES To develop a graphical method for displaying IOL calculation formulas in 3 dimensions, and to describe amethod that uses the most accurate and current information on IOL formulas, adjustments, and lens design to create one "super surface" and develop an IOL "super formula." DESIGN, SETTING, AND PARTICIPANTS A numerical computing environmentwas used to create 3-D surfaces of IOL formulas: Hoffer Q, Holladay I, Holladay I with Koch adjustment, Haigis, and SRK/T. The surfaces were then analyzed to determine where the IOL powers calculated by each formula differed by more than 0.5, 1.0, and 1.5 diopters (D) from each of the other formulas. Next, based on the current literature and empirical knowledge, a super surface was rendered that incorporated the ideal portions from 4 of the 5 formulas to generate a super formula. Last, IOL power values of a set of 100 eyes from consecutive patients at an eye institute were calculated using the 5 formulas and super formula. The study was performed from December 11, 2014, to April 20, 2015. Analysis was conducted from February 18 toMay 6, 2015. MAIN OUTCOMES AND MEASURES Intraocular lens power value in diopters and the magnitude of disparity between an existing individual IOL formula and our super formula. RESULTS In the 100 eyes tested, the super formula localized to the correct portion of the super surface 100% of the time and thus chose the most appropriate IOL power value. The individual formulas deviated from the optimal super formula IOL power values by more than 0.5 D 30% of the time in Hoffer Q, 16%in Holladay I, 22%in Holladay I with Koch adjustment, 48%in Haigis, and 24%in SRK/T. CONCLUSIONS AND RELEVANCE A novelmethod was developed to represent IOL formulas in 3 dimensions. An IOL super formula was formulated that incorporates the ideal segments from each of the existing formulas and uses the ideal IOL formula for an individual eye. The expectation is that this method will broaden the conceptual understanding of IOL calculations, improve clinical outcomes for patients, and stimulate further progress in IOL formula research.

Original languageEnglish (US)
Pages (from-to)1431-1436
Number of pages6
JournalJAMA ophthalmology
Issue number12
StatePublished - Dec 1 2015

ASJC Scopus subject areas

  • Ophthalmology


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