What is the name of the transparent membrane that protects a frog's eye?

The transparent membrane that protects a frog's eye is known as the nictitating membrane. This unique structure serves several important functions. Primarily, it acts as a protective barrier, allowing frogs to keep their eyes moist while still being able to see, particularly when they are submerged in water. Additionally, the nictitating membrane can help shield the eyes from debris and potential harm when the frog is hunting or moving through its environment.

In contrast, the conjunctiva is a thin membrane that covers the inner surface of the eyelids and part of the eyeball but is not specialized for protection in the same way. The cornea is the clear front part of the eye that covers the iris and pupil, facilitating light entry but does not possess the same protective qualities as the nictitating membrane. The retina, on the other hand, is the layer at the back of the eye that detects light and sends visual signals to the brain, playing a key role in the process of vision but does not serve a protective function.