But a new study suggests it might one day be possible. Scientists recently succeeded in applying a biological film to rat retinas that is capable of restoring light sensitivity.

The film, called P3HT:PCBM, is a mixture of two organic compounds that are highly sensitive to light (one of them is used in the construction of solar power cells). To test the film, scientists from the Italian Institute of Technology in Genoa, bred two groups of rats: one with perfect eyesight, and one subjected to substantial ocular degeneration.

After dissection, researchers separated the rats' eyes into individual components in an organic bath, and isolated their retinas. The researchers placed the retinas on either a plain glass or a glass coated with P3HT:PCBM, then measured each retina's responsiveness to light.