Tag Archives: modifying corneal refractive index

In-home (one day in the future) eyesight correction

It’s easy to become blasé about ‘futuristic’ developments but every once in a while something comes along that shocks you out of your complacency as this March 8, 2018 news item did for me,

A revolutionary, cutting-edge technology, developed by researchers at Bar-Ilan University’s Institute of Nanotechnology and Advanced Materials (BINA), has the potential to provide a new alternative to eyeglasses, contact lenses, and laser correction for refractive errors.

The technology, known as Nano-Drops, was developed by opthamologist Dr. David Smadja from Shaare Zedek Medical Center, Prof. Zeev Zalevsky from Bar-Ilan’s Kofkin Faculty of Engineering, and Prof. Jean-Paul Moshe Lellouche, head of the Department of Chemistry at Bar-Ilan.

It seems like it would be eye drops, eh? This March 8, 2018 Bar-Ilan University press release, which originated the news item, proceeds to redefine eyedrops,

Nano-Drops achieve their optical effect and correction by locally modifying the corneal refractive index. The magnitude and nature of the optical correction is adjusted by an optical pattern that is stamped onto the superficial layer of the corneal epithelium with a laser source. The shape of the optical pattern can be adjusted for correction of myopia (nearsightedness), hyperopia (farsightedness) or presbyopia (loss of accommodation ability). The laser stamping onto the cornea [emphasis mine] takes a few milliseconds and enables the nanoparticles to enhance and ‘activate’ this optical pattern by locally changing the refractive index and ultimately modifying the trajectory of light passing through the cornea.

The laser stamping source does not relate to the commonly known ‘laser treatment for visual correction’ that ablates corneal tissue. It is rather a small laser device that can connect to a smartphone [emphasis mine] and stamp the optical pattern onto the corneal epithelium by placing numerous adjacent pulses in a very speedy and painless fashion.  Tiny corneal spots created by the laser allow synthetic and biocompatible nanoparticles to enter and locally modify the optical power of the eye [emphasis mine] at the desired correction.

In the future this technology may enable patients to have their vision corrected in the comfort of their own home. [emphasis mine] To accomplish this, they would open an application on their smartphone to measure their vision, connect the laser source device for stamping the optical pattern at the desired correction, and then apply the Nano-Drops to activate the pattern and provide the desired correction.

Upcoming in-vivo experiments in rabbits will allow the researchers to determine how long the effect of the Nano-Drops will last after the initial application. Meanwhile, this promising technology has been shown, through ex-vivo experiments, to efficiently correct nearly 3 diopters of both myopia and presbyopia in pig eyes.

The researchers do not seem to have published a paper about this work. However, there is a March 19, 2018 article by Shoshanna Solomon for the Times of Israel, which provides greater  detail about how you or I would use this technology,

The Israeli researchers came up with a way to reshape the cornea, which accounts for 60 percent of the eye’s optical power. They tried out their system on the eyes of dead pigs, which have an optical system that is very similar to that of humans.

There are three steps to the technology that is now in development.

The first step requires patients to measure their eyesight via their smartphones. There are already a number of apps that do this, said Smadja. The second step requires the patients to use a second app — being developed by the researchers — which would have a laser device clipped onto the smartphone. This device will deliver laser pulses to the eye in less than a second that etch a shallow shape onto the cornea to help correct its refractive error. During the last stage, the Nano-Drops — made up of nontoxic nanoparticles of proteins — are put into the eye and they activate the shape, thus correcting the patients’ vision.

“It’s like when you write something with fuel on the ground and the fuel dries up, and then you throw a flame onto the fuel and the fire takes the shape of the writing,” Smadja explained. “The drops activate the pattern.”

The technology, unlike current laser operations that correct eyesight, does not remove tissue and is thus noninvasive, and it suits most eyes, expanding the scope of patients who can correct their vision, he said.

It’s a good article and, if you have the time, it’s worth reading in its entirety. Of course, it’s a long from ‘being in development’ to ‘available at the store’.