Conjunctivitis, keratitis and iridocyclitis are common causes of bloodshot eyes in the elderly. Conjunctivitis is usually caused by dirty hands rubbing the eyes and other habits that do not pay attention to eye hygiene, resulting in pathogenic microorganisms in the external environment to invade the conjunctival tissues and triggered by infection, in addition to eye congestion, eye secretions will also occur and other symptoms. Keratitis is an inflammation of the cornea caused by the destruction of the corneal defense barrier due to external harmful factors. In addition to the symptoms of eye congestion, there will also be eye pain, photophobia, foreign body sensation, tearing, and vision loss. Iridocyclitis is mostly caused by autoimmune reaction, eye congestion will be accompanied by vision loss, eye pain and other manifestations. There are many causes of eye congestion in the elderly, if it cannot be relieved for a long time or is accompanied by eye pain, increased secretion and other discomforts, it is recommended to go to the ophthalmology department of the hospital as soon as possible to find out the specific causes, and then only through targeted treatment can the symptoms be eliminated as soon as possible.