Bubbles Reshape Lens to Treat Presbyopia

The predominant theory is that fibers created in the intraocular lens accumulate and stiffen, thus making the lens less flexible. Without that flexibility, the lens can't change shape to focus on near objects, a process called accommodation. One way to potentially solve presbyopia is to remove some fibers to restore the lost flexibility. Laser correction of the intraocular lens for presbyopia has been proposed, but until now there has been no method to know where to remove these fibers or how much to remove.

Researchers at the University of Michigan department of Biomedical Research (Ann Arbor, MI, USA) have developed a tool that uses ultrafast laser pulses to create tiny gas bubbles within the intraocular lens. Before the bubbles diffuse, researchers hit them with high frequency sound waves, which push the bubbles against neighboring lens fibers. Part of the sound is reflected, and from the characteristic of the reflection, the location of the bubble can be determined, in a procedure similar to ultrasound imaging. In this way, researchers can measure how far the bubbles have moved based on the force applied, and thus measure the pliability of the lens.

"The bubbles show you where the laser should cut,” said Professor Matthew O'Donnell, chair of the U-M Department of Biomedical Research, who developed the method with Kyle Hollman, assistant research scientist and adjunct lecturer, and graduate student Todd Erpelding. "If it's still too hard, you cut some more. If it's soft enough, you stop.”

The tool is a new application of microscale bubbles, which scientists have experimented with for years in the areas of drug delivery, tumor destruction, and other medical applications.



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University of Michigan department of Biomedical Research