As I theorized in Hawking Eye Radiation, I think there are some good reasons to believe that the eye produces light. The question becomes, ‘how does it produce this light?’
I learned recently that LEDs act as light sensors when turned off. I think that this could be the way that the eye works. I don’t mean how the eye works in the traditional sense, but how this potential added sense could be explained.
If the eye produces light during normal hours, even if it is a relatively small amount, perhaps the light shuts off at a certain point each day. Maybe when we get tired. And if the eye shuts off when we get tired, current would flow through this light sensor, increasing the electric charge on the brain. And that would make the subject more susceptible to seizures.
Next, is to determine, if true, how this system works.