A new eye drop tested in dogs shows promising results in improving the vision of those with cataracts. If successfully tested in humans, it could be the first nonsurgical treatment for this medical condition.

Researchers led by Dr. Kang Zhang, chief of ophthalmic genetics with the Shiley Eye Institute at the University of California, San Diego, found that the organic compound called lanosterol can shrink the cataracts when used as an eye drop.

Cataract is the leading cause of blindness worldwide and in the U.S., characterized with clouding of the eye's lens. It blocks the light from entering the lens, making it difficult to see clearly until it leads to blindness. Some are born with it, while others develop the condition at any age. Approximately 21 million Americans (17.2 percent) aged 40 and above have cataracts on both eyes, and this is projected to increase to 30 million by 2020, according to the Centers for Disease Control Prevention.

The researchers tested the lanosterol eye drop on seven dogs with cataracts. After six weeks of using the eye drop, three dogs recovered their full vision in six weeks, while the rest showed vision improvement.

"The results we have point to a new nonsurgical treatment of cataracts that can be used for people who might have moderate cataracts or do not have access to surgery," Zhang told HealthDay News.

Currently, the only way to remove cataracts is through surgery, so having a nonsurgical and cheaper option will be considered as a medical breakthrough.

"It would have a huge public health impact," Dr. Robert B. Bhisitkul, a professor of ophthalmology at the UC San Francisco School of Medicine who was not involved in the research, told The Los Angeles Times. "Preventing or reversing cataracts with an eyedrop has been the Holy Grail in ophthalmology since the field began."

Zhang said that the team plans to start human testing within two years.

The study was published in the July 22 issue of the journal Nature.