The ophthalmic nerve is a branch of the trigeminal nerve, which is the fifth cranial nerve. It is primarily responsible for transmitting sensory information from the forehead, upper eyelid, and parts of the nose. This nerve plays a crucial role in providing sensation to the skin and mucous membranes in these areas. The ophthalmic nerve divides into three main branches: the frontal nerve, nasociliary nerve, and lacrimal nerve. Each of these branches serves specific regions of the face and eyes, helping to relay important sensory information to the brain. This function is essential for protecting the eyes and maintaining overall facial sensation.