Experimental Eye Drops Restored the Ability to See Light in Blind Mice

Prosthe6 molecules change shape under light and activate the mGlu6 protein on ON bipolar cells. This creates a chemical prosthesis: when there is light, a signal is transmitted; when there is no light, the system is silent. Importantly, the activation threshold is close to ordinary indoor light or a cloudy day. No special glasses or boosted lighting are needed.

In genetically blinded zebrafish larvae, the optokinetic reflex returned—rapid tracking eye movements. In mouse models of retinitis pigmentosa and macular degeneration, innate behavior came back: the animals again preferred dark areas and avoided bright light. This is not a learned trick but a natural response to illumination. Two variants of the substance—prosthe6-12 and prosthe6-15—worked both after injection and as drops.

The authors emphasize the limits of the method. It does not repair dead photoreceptors and does not stop the disease itself. It only reactivates the remaining circuit. Human application is still a long way off: safety data, effect duration, and a convenient drop formulation are needed. But the principle itself looks elegant—without gene therapy, without a chip in the eye, and without a laboratory spotlight.

Sources:

1. Institute for Bioengineering of Catalonia (IBEC). "Experimental eye drops help blind mice see again." ScienceDaily (28 August 2026).
2. Sortino R. et al. "Restoration of Saccadic Eye Movements and Visually Guided Behavior in Ambient White Light with Photoswitchable Small Molecules." Journal of the American Chemical Society (2026). DOI: 10.1021/jacs.5c18611.