Your eyes need a constant layer of tears — called the "tear film"— to maintain and protect the ocular surface. The tear film is a layer of substances secreted by glands around the eyes and intended to keep the eye surfaces constantly lubricated.
Your eyes need a constant layer of tears — called the "tear film"— to maintain and protect the ocular surface. The tear film is a layer of substances secreted by glands around the eyes and intended to keep the eye surfaces constantly lubricated.