I came across a Watersnake with a possible retained eye cap while at the Sequoyah National Wildlife Refuge in Oklahoma. I had no idea what was wrong with this snakes eye and had to do some research when I got home. I read that snakes do not have eyelids like we have but instead they have specially adapted scales over their eyes called eye caps (also known as spectacles) to protect their eyes. These eye caps are normally shed off along with the skin of a snake during their normal shed cycle, but sometimes the caps do not come off properly and snakes get retained eye caps. The retained eye caps can cause problems for the snake.
I also read that snake mites or infections of the eye or surrounding tissues may contribute to retained eye caps.
I was able to get very close to this Watersnake as long as I stayed on the side with the bad eye. As soon as I moved around to the other side the snake took off quickly into the brush.
Watersnake With Possible Retained Eye CapWatersnake at Sequoyah National Wildlife Refuge in Oklahoma