A new medical procedure using "nano" eye drops could help millions by providing a simple alternative to laser correction, glasses and contact lenses, according to a recent study by Israeli researchers.The three-step method is designed to address short-sightedness, long-sightedness and cornea defections, some of the most common eye conditions, say scientists who carried out trials at Israel's Bar-Ilan University.The procedure uses eye-drops to adjust the refraction of light through the cornea, a protective layer that rests above the eye's lens and iris - and can be mostly carried out from the comfort of a patient's home.In the first step, a smartphone app measures the adjustment required to the eye. In stage two, an optical pattern is "stamped" onto the cornea's surface using a small laser, in a minor surgical procedure. In the final stage, nano-particle eye drops are applied by the patient, activating the pattern and ultimately repairing eyesight.While the treatment only provides a temporary fix for certain eye conditions, it prevents the need to remove significant portions of the cornea required in other operations. It therefore offers improved eyesight for people suffering from weak or thin corneas who are unable to undergo laser correction.The procedure could also prove appealing to people wanting to forego invasive surgery but who still want to go without glasses, said Doctor David Smadja, part of a team of researchers at Bar-Ilan University who conducted the new study."The idea is to find a way to modify the trajectory of light with eye drops, not just by changing the shape as we are doing with glasses, contact lenses or laser refractive surgery, but by modifying the refractive index of the cornea. So we can just play with the light and change the trajectory in order to get all the light in focus," said Smadja, who also heads the Refractive Surgery department at Jerusalem's Shaare Zedek Medical Center."We only treat the first upper layer of cells of the cornea, this is why the process is very fast. It is so simple and fits for everyone, no matter how thick his cornea is, what their age is or exactly what the visual problem is," said Professor Zeev Zalevsky from the Bar-Ilan laboratory, where most of the experiment was conducted.The researchers conducted initial tests on pig eyes, correcting short-sightedness and a lens elasticity condition called presbyopia in an effect that lasted for two hours. Their next experiments, to be conducted under general anesthesia in rabbits, will determine the length of the nano-drops' effectiveness. The nanoparticle eye drops used in the final stage consist of biologically compatible material that has already been in used in pharmaceutical products, said Professor Jean-Paul Lellouche of the Department of Chemistry, who participated in the study.Lellouche said he was confident that using the eye drops periodically for improving optical functionality in humans was safe, and hopes that with enough funding the procedure will be ready for use by the end of 2019.About 285 million people globally suffer from visual impairment, including 39 million who are blind and 246 million more who have poor vision, according to the World Health Organization (WHO).The main causes of moderate and severe vision impairment are uncorrected nearsightedness, farsightedness and astigmatism, a problem with the eye's lens affecting its ability to focus, according to the WHO.