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Digital ultrasound could improve custom ablations
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NEW YORK — Imaging a cornea with very high frequency (VHF) three-dimensional digital ultrasound could improve visual outcomes of laser refractive surgery for irregular astigmatism, according to Dan Z. Reinstein, MD. Dr. Reinstein believes irregular stromal astigmatism is undertreated because it is concealed by epithelial remodeling over the stromal surface.
Dr. Reinstein is a co-inventor of the Artemis VHF three-dimensional digital ultrasound device (Ultralink LLC), which recently received U.S. marketing approval. The Artemis can provide three-dimensional maps of the epithelium, flap and residual stromal thickness with 1 µm reproducibility, according to Dr. Reinstein. Incorporating the epithelial data into customized ablation models is "likely to improve the correction of asymmetric astigmatism," he said in an interview with Ocular Surgery News.
After imaging asymmetric corneas for more than a decade using the VHF ultrasound, Dr. Reinstein determined that almost all corneas with asymmetric astigmatism possess an asymmetric epithelium.
"There is this compensatory effect; asymmetric stromal surfaces command the epithelium to make a compensatory change," Dr. Reinstein said. He believes the reason that procedures such as Topolink are unpredictable is because they are measuring the wrong surface.
An in-depth interview with Dr. Reinstein will appear in the September 1, 2001, issue of Ocular Surgery News.