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Comment & Response |

Origin of Multiple Formula Use to Calculate Intraocular Lens Power—Reply

John G. Ladas, MD, PhD1; Albert S. Jun, MD, PhD1; Uday Devgan, MD2
[+] Author Affiliations
1Wilmer Eye Institute, Baltimore, Maryland
2Jules Stein Eye Institute, University of California, Los Angeles
JAMA Ophthalmol. 2016;134(7):848-849. doi:10.1001/jamaophthalmol.2016.1049.
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In Reply We appreciate Dr Hoffer’s interest in our article and respect his contributions to the field as well as the contributions of others mentioned in his letter. He mentions the “concept” of multiple formulas and how it evolved because no one formula gives acceptable results in every situation. We think everyone can agree that access to multiple formulas was needed, but perhaps the change of the SRK I formula to the SRK II formula (and the subsequent adjustment to the A-constant based on axial length) was the first solution to this dilemma prior to our article.1 Indeed, as Hee stated, we “formalized” the approach to the use of many formulas.2 We chose our formula based on peer-reviewed literature. We could have included more formulas if we had wanted, but we decided to choose formulas already validated in the literature.


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July 1, 2016
Kenneth J. Hoffer, MD
1Stein Eye Institute, University of California, Los Angeles2St Mary’s Eye Center, Santa Monica, California
JAMA Ophthalmol. 2016;134(7):847-848. doi:10.1001/jamaophthalmol.2016.1043.
July 1, 2016
Michael R. Hee, MD, PhD
1Pacific Eye Specialists, Daly City, California
JAMA Ophthalmol. 2016;134(7):848. doi:10.1001/jamaophthalmol.2016.1046.
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