Customized IOL calculator helps cataract surgeons navigate lens choices

An IOL calculator must take into consideration the various challenges cataract surgeons face when making an IOL selection and be easily accessible.

Reviewed by Samir I. Sayegh, MD, PhD, FACS

Champaign, IL-Cataract surgeons can use IOL calculators to help achieve the best possible surgical outcomes and spend less time calculating the right IOL choice, said Samir I. Sayegh, MD, PhD, FACS, The Eye Center, Champaign, IL.

Some challenges that cataract surgeons face during the IOL selection process is calculating sphere, obtaining biometric data from multiple devices, and figuring out what other factors to include, such as multiple Ks, posterior astigmatism, and anterior chamber depth, Dr. Sayegh said.

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Yet other challenges that cataract surgeons grapple with include toric-related issues, such as using a fixed or variable “toricity ratio” and the sometimes-bewildering variety of IOLs and manufacturers.

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One tool that can help cataract surgeons is a universal, yet customized, IOL calculator, Dr. Sayegh said.

Such a calculator would need to include several features, he explained.

What surgeons need to know


What surgeons need to know

These include multiple approaches such as well-tested and openly published formulae (for instance, SRK/T, HofferQ, and Haigis), multiple toric computation paradigms (including fixed and variable toricity ratios), access to an extensive database of IOLs but also allow for a surgeon’s customization, and multiple ranking preferences that minimize sphere error or astigmatism first-or, more global criteria that optimize sphere and cylinder residuals simultaneously.

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Such a calculator would need to be Internet-accessible and easy to access online, be it on a computer, mobile device, or phone, Dr. Sayegh said.

The core calculator would need to include IOL power, toric options, ranking, and preferences. The lens database that is part of the system would need to include options from the variety of manufacturers and provide monofocal, aspheric, toric, and multifocal choices.

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Dr. Sayegh has designed UniversIOL, an IOL calculator that helps meet the challenges outlined.

He said his calculator is extensive and has a growing universal database of IOL types and IOLs. The calculator also provides a choice of formulae for sphere and toric computation, a choice of computational strategies, and a choice of IOL-ranking criteria that is selectable by each surgeon.

Dr. Sayegh’s calculator, called UniversIOL, is available at A demo can be accessed at

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Samir I. Sayegh, MD, PhD, FACS


Dr. Sayegh has no financial interest in the subject matter.

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