Red blood in eyes with OK lenses may be caused by OK lenses rubbing cornea, keratitis, conjunctivitis and other reasons. 1. OK lens rubbing cornea: OK lens is a kind of special contact lens, belongs to a kind of corneal contact lens, commonly used in non-surgical correction, if wearing OK lens eye with red blood, then it may be caused by wearing OK lens rubbing cornea, also may be accompanied by the symptom of tearing. 2. Keratitis: If OK lenses are worn for a long time, it may lead to excessive stimulation of the cornea, which may cause keratitis. Under the effect of the condition, it is easy to lead to redness in the eyes with OK lenses, and it may be accompanied by swelling of the eyes and loss of vision. 3. Conjunctivitis: Conjunctivitis is usually related to improper cleaning of OK lenses, which leads to bacterial infection, etc. Conjunctival congestion may occur, resulting in redness in the eyes with OK lenses, which may be accompanied by itching of the eyes, increased eye secretion and other symptoms. When wearing OK lenses, it is recommended to clean them regularly to avoid bacterial growth, and to wear them correctly as prescribed by your doctor.