Dry eye disease is characterised in part by depletion of NADPH, a molecule corneal cells need to neutralise damaging reactive oxygen species. Researchers at the NUS Department of Chemical and Biomolecular Engineering approached that deficit from an unexpected direction. Their formulation, called LEAF, is a nanosized extract of spinach thylakoid grana, the membrane structures where photosynthesis captures light energy, delivered as eye drops so that corneal cells can generate NADPH from ambient light.
The mechanism is intended to interrupt a self-reinforcing cycle. Oxidative stress drives inflammation, inflammation damages cells, and damaged cells are less able to maintain their antioxidant capacity. By restoring the reducing power directly, the drops aim to break that loop rather than suppress one of its symptoms. Preclinical work was conducted with ophthalmologists at the Eye Centre of the Second Affiliated Hospital, Zhejiang University, and the findings were published in Cell.
The reported effects are substantial. In patient tear samples, LEAF raised NADPH roughly twentyfold and cut hydrogen peroxide by over 95 per cent. In a preclinical trial it restored corneal tissue to near-healthy levels within five days, outperforming the comparator Restasis, and two months of safety testing showed no adverse effects. Dry eye disease affects more than 1.5 billion people worldwide, with the United States economic burden estimated at 3.84 billion dollars annually.
The results remain preclinical and clinical trials are planned, so the therapeutic claim is unproven in humans. The conceptual contribution is nonetheless striking: using a plant photosynthetic apparatus as a light-driven cofactor generator inside mammalian tissue. If the approach holds up, the same logic might apply wherever a tissue is both reducing-equivalent depleted and physically accessible to light.