Cataracts are the most common cause of blindness in humans and account for half of blindness cases worldwide. Currently the only available treatment for the debilitating growths, which affect tens of millions of people worldwide, is going under the knife. While surgery is generally simple and safe, the number of people who require it is set to double in the next 20 years as the populations age. And for many people, it remains prohibitively costly. An eye drop tested on dogs suggests that cataracts could one day be cured without surgery. The study revealed that a naturally-occurring molecule called lanosterol, administered with an eye dropper, shrank canine cataracts.
The chain of research leading to the potential cure began with two pediatric patients from families beset with a congenital, or inherited, form of the condition. Lead researcher Kang Zhang of Sun Yat-sen University in Guangzhou and colleagues discovered that these two patients shared a mutation in a gene critical for producing lanosterol, which the researchers suspected might impede cataract-forming proteins from clumping in normal eyes.
In a first set of laboratory experiments on cells, they confirmed their hunch that lanosterol helped ward off the proteins. In subsequent tests, dogs with naturally-occurring cataracts received eye drops containing lanosterol. Following six weeks of treatment, the size and characteristic cloudiness of the cataracts had decreased, the researchers reported.
The authors concluded, "Our study identifies lanosterol as a key molecule in the prevention of lens protein aggregation and points to a novel strategy for cataract prevention and treatment."
The study is reported in Nature.