What infection affects the outer layer of the eye?

The infection that affects the outer layer of the eye is conjunctivitis. Conjunctivitis, commonly known as pink eye, involves inflammation of the conjunctiva, which is the thin, transparent membrane that covers the white part of the eyeball and lines the inside of the eyelids. This condition can be caused by infections, allergens, or irritants and typically presents with symptoms like redness, itching, and discharge.

In contrast, the other options refer to infections affecting different layers or parts of the eye. Uveitis refers to inflammation of the uvea, the middle layer of the eye, which includes the iris, ciliary body, and choroid. Keratitis involves inflammation of the cornea, the clear front surface of the eye. Retinitis is inflammation of the retina, the light-sensitive tissue at the back of the eye. Each of these conditions involves different structures of the eye and their symptoms and treatments also differ significantly from those of conjunctivitis.