What is the outermost layer of the eye called?

The outermost layer of the eye is known as the conjunctiva. This thin, transparent membrane covers the white part of the eyeball (sclera) and the inner surfaces of the eyelids. Its primary function is to provide protection and lubrication to the eye, preventing dryness and irritation. The conjunctiva also plays a role in immune defense against pathogens, helping to maintain the health of the eye.

The cornea, while it is part of the outer structure of the eye, actually serves as the transparent front part that covers the iris and pupil. It is important for focusing light but is not the outermost layer. The retina, located at the back of the eye, is crucial for vision as it contains photoreceptors that convert light into neural signals but is well inside the eye structure. The iris, meanwhile, is the colored part of the eye that regulates the size of the pupil, controlling how much light enters the eye but is also not the outermost layer. Therefore, the conjunctiva is indeed the correct answer when referring to the outermost layer, providing a barrier and protective surface.