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IOL power changes with ciliary body action possible
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An IOL designed with flexible material can be manipulated when placed between a scleral-fixated rigid plane and the ciliary muscles, allowing for an accommodative change of up to 50 D in a laboratory model, according to researchers.
Joshua Ben-nun, MD, and Jorge L. Alió, MD, PhD, constructed an implantable measuring device to simulate lens action and implanted the device in monkey eyes. Based on the measurements, an accommodating IOL prototype was also built and implanted in the monkey eyes. Pharmacologic agents were used to achieve ciliary relaxation and spasm, the researchers said. Ultrasound biomicroscopy imaging was used to document the active changes of the IOL flexible lens curvature as related to the ciliary muscles status.
In the lab, the model lens produced more than 50 D of accommodation; ultrasound biomicroscopy showed changes in lens curvature between cyclospasm to cyclopegia of calculated 9 to 53 D for flexible material with a refractive index of 1.41, the researchers said.
They said the lenses used in this study “generated power by direct pressure of the piston on the silicone gel, with maximal power achieved when the ciliary muscles are relaxing.” Preliminary results from the preclinical trials indicated “rapid and uncomplicated adjustment to such a mechanism,” they said.
“To our knowledge, this is the first report of an IOL capable of performing real changes of wide magnitude in IOL power related to the action of the ciliary body,” they said.
The study is published in the Journal of Cataract and Refractive Surgery.