A visual simulator can provide patients with the experience of vision with multifocal intraocular lenses before actual implantation, helping to manage patients' expectations.
How technology works
The device contains an optotunable lenses. Using a custom high-speed electronic driver, the lenses can change focus rapidly by a process called temporal multiplexing.
“With periodic variations of the optical power at high speed, above 50 Hertz, static appearance of multifocal retinal images are provided by mapping spatial distribution in a lens into temporal distribution in the optotunable lens,” Prof. Marcos described.
Dr. Marcos demonstrated this in a trifocal FineVision IOL. The map in the IOL is defined with a set of coefficients; the data show how much time the lens spends at the different power additions.
With a trifocal lens the coefficients are at three different foci. This process can be performed with different coefficients and simulate extended-depth-of-focus lens types and different energy distributions.
“We also control for dynamic effects in the lens so that we can really map the true focus performance of the lens,” she said. A comparison of the performance of an actual commercial IOL with the simulation showed how well the images of the two matched.
When the SimVisGekko was taken into the clinic, it performed well. Prof. Marcos said researchers have found that the device replicates mIOLs.
“We performed the test with a trifocal IOL in the SimVis preoperatively and the patient was ultimately implanted with the lens,” she said. “We found that in patients with clear lenses and those with cataracts, the pre-operative (with SimVis) and post-operative (with the implanted mIOL) defocus curved matched.
In the presence of a cataract, there is a shift down because of the light distribution caused by the cataract, but the shape of the defocus focus curve is well captured.”