Why did Sir Isaac Newton stick a needle in his eye?

Purkyně's self-experimentation looks positively tame compared to a young Isaac Newton's decision to take a bodkin (a large sewing needle) and “put it betwixt my eye and bone as neare to [the] backside of my eye as I could. read more

Or more accurately, he pushed a needle behind his eye and with it, indented the sclera. The needle never entered the eye. By doing so, he stimulated his retina in many spots and noted a"phosphene" or glowing spot that resulted from the pressure. read more

But, yes, Isaac Newton did nearly go blind from staring into the sun and also stuck a needle into the back of his eye. Here's a few considerations about Isaac Newton: 1. About half of Newton's working life was spent practicing alchemy (the pursuit of transforming base metals into gold). read more

He did indeed. Or more accurately, he pushed a needle behind his eye and with it, indented the sclera. The needle never entered the eye. By doing so, he stimulated his retina in many spots and noted a"phosphene" or glowing spot that resulted from the pressure. From this he was able to"map" his own retina against where he saw the spots. read more