New eye drops to prevent common cause of blindness

Researchers have developed eye drops that could prevent vision loss after retinal vein occlusion, a major cause of blindness for millions of adults worldwide. The study suggests that the experimental therapy – which targets a common cause of neurodegeneration and vascular leakage in the eye – could have broader therapeutic effects than the existing drugs.

Retinal vein occlusion occurs when a major vein that drains blood from the retina is blocked, usually due to a blood clot. As a result, blood and other fluids leak into the retina, damaging specialised lightsensing neurons called photoreceptors.

Standard treatment for the condition currently relies on drugs that reduce fluid leakage from blood vessels and abnormal blood vessel growth. These therapies require repeated injections directly into the eye, and the treatment ultimately

fails to prevent vision loss in majority of the cases.

“The new treatment targets an enzyme called caspase-9. Under normal conditions, caspase-9 is believed to be primarily involved in programmed cell death, a tightly regulated mechanism for naturally eliminating damaged or excess cells,” said study researcher Carol M. Troy from the Columbia University in the US.

The study found that a highly selective caspase9 inhibitor, delivered in the form of eye drops, improved a variety of clinical measures of retinal function in a mouse model of the condition.