The unassuming vial of eye drops could easily belong on a pharmacy shelf. But swirling inside are microscopic bits of photosynthetic machinery made from plants. Within minutes of giving the drops to mice, their eyes gain an extraordinary ability beyond that of any mammal. Like a leaf, they can now harness the power of sunlight.

Photosynthetic eyes sound like they’re straight out of science fiction, but there’s a practical use researchers are after. Chemical reactions during photosynthesis generate powerful antioxidants that ward off inflammation and could potentially treat a range of health conditions.

Called LEAF, the technology is creative, effective, and simple. Its main ingredient can be found in grocery store spinach.…