Trichiasis, recognized since the time of Hippocrates, is a cause of ocular irritation that may result in scarring of the cornea and threaten sight. We have reviewed the original Greek medical texts made from the 1st to the 7th century ce and present the existing medical knowledge relating to trichiasis, including its clinical picture, cause, diagnosis, and treatment. Recognition of trichiasis as a stage of trachoma and its distinction from pseudotrichiasis gave the impetus for physicians of the era to use a significant number of pharmaceutical and surgical treatments.