Based on the typikon of the Imperial Monastery of the Pantocrator of Constantinople (12th century) and the manuscripts used in the Byzantine hospitals as well as the published Lives of the Saints and other related sources, it is undeniable that special ophthalmological departments existed in the xenones of Byzantium. It is also proven, that specific ophthalmological therapy was practised here including surgery and particularly in the cataract operation. This last operation is attested to, not only by the medical writings of Byzantine writers but also from the therapies of the physician-saints Cosmas and Damian.
A complete picture of Byzantine ophthalmological medical knowledge as well as applied medical therapies is available through the systematic study of written works, the most relevant being those of Oribasios, Aetius of Amida, Alexander Trallianos, Paul of Aegina, Theophilus Protospatharios, John Actuarios, Theophanes Nonnos, Meletios Monachos (the Monk), Nemesios the Bishop of Emesa, and others. These authors, deeply influenced by ancient Greek tradition, combine the ancient works with the fruits of their own practical applications in ophthalmology. In this rich medical oeuvre we find the complete description of many ophthalmological diseases and conservative therapies in the works of Aetios of Amida (which encompass a complete medical ophthalmological textbook of the period), the opthalmological therapies of Nonnos Theophanes (who recommends a pharmaceutical textbook of this period), the techniques of ophthalmological surgery described by Paul of Aegina, the differential diagnostics of John Actuarios and finally the rich ophthalmological work of Alexander Trap llanos. He prepared a monograph of eye diseases, based chiefly on the medical tradition of ancient Greece in the field of opht]halmology and provided, apart from Greek theoretical medical instruction, practical hospital medical experience [9,12,13,16,17].
According to the opinion of the Byzantinologist, Professor Phaidon Koukoules, ophthalmology amounted to a separate and special field in Byzantium. 'Among the specialist doctors,' he writes, 'are also those who cure suffering or weak eyes', as the Byzantines termed them, that is those who completely lacked their sight. For the relief of suffering eyes, ophthalmologists recommended that sufferers avoid looking at very bright objects and that they look rather at various flowers or bushes or to look at bluish