Eyeworld

SEPTEMBER 2021 | EYEWORLD | 45 C by Liz Hillman Editorial Co-Director About the physicians Kenneth J. Hoffer, MD Clinical Professor of Ophthalmology Stein Eye Institute University of California, Los Angeles Los Angeles, California Jennifer Loh, MD Loh Ophthalmology Associates Miami, Florida H. John Shammas, MD Clinical Professor of Ophthalmology Keck School of Medicine of the University of Southern California Los Angeles, California In 1999, Dr. Hoffer said he became the first ophthalmologist in the Western Hemisphere to acquire an IOLMaster 500 (Carl Zeiss Meditec), the first optical biometer. Ten years later, in 2009, he gained access to the LENSTAR LS900 (Haag-Streit). Dr. Hoffer said he now has access to every optical biometer. When to consider a new biometer The first reason one might want a new biometer is if it isn't functioning properly. If it is function- ing and producing accurate results, Dr. Hoffer said it's still useful. "If you have a biometer, whether it's an ultrasound or optical, and it's working properly, an ophthalmologist doesn't need to every 5 or even 10 years turn around and buy a new biom- eter," he said. There are three things you want out of a biometer, Dr. Hoffer said: axial length, corneal power and astigmatism, and anterior chamber depth. "There are other things you can get but those are the essentials," he said. B iometry is essential for IOL power calculations, but when might you need a new biometer? What should you look for? What is there to know about this technology, how it evolved, and where it is today? If you're going to start talking about biom- etry, the first stop is Kenneth J. Hoffer, MD. Dr. Hoffer was the first ophthalmologist in the U.S. to use an ultrasound biometer to measure the axial length of the eye for IOL power calcula- tions in 1974. In 1999, he was the first in the country to use an optical biometer and conduct a study that found optical biometry was easier and more accurate than ultrasound immersion biometry. Dr. Hoffer said he has been the first U.S. physician to use or try every optical biome- ter that's been introduced in the country. "I became the grandfather of IOL power cal- culations and biometry just by hanging around a long time," Dr. Hoffer said. Biometry history In April 1974, Dr. Hoffer first used an ultra- sound biometer to measure axial length for a lens power calculation. "There were ophthalmologists in the United States who were doing lens implantation, but there weren't any sophisticated calculations. They were implanting an 18 D lens in every pa- tient's eye. If you had a patient who was a –9 D myope, restricted by thick glasses, they'd get an implant and be a –9 D postop. Obviously, if you could adjust the lens implant power, you could get them out of glasses overall," he said. Dr. Hoffer learned of A-scan biometers that could measure the length of the eye when he was at a course in Long Island, New York, in 1972. He said he initially laughed and won- dered who would care about the length of the eye. The ophthalmologist who introduced this device, Dr. Hoffer said, had the last laugh because Dr. Hoffer called him 2 years later to ask the name of the machine, acquired one, and used the measurement for a lens power calcula- tion for his first IOL implantation using his new Hoffer formula. Looking for a new biometer? Here's what you need to know continued on page 46 "After 50 years in this field, if I felt the need or had to buy a new instrument, I would make sure it was a swept-source OCT because of the technology being so much better, even though the result is about the same." —Kenneth J. Hoffer, MD

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