The Arabs were much interested in ophthalmology. In the ninth century, Hunayn Ibn-Ishak (Joannitius) translated to Arabic the Greek literature on the eye. As mentioned before, Al-Razi described the changes in the caliber of the eye produced by relaxation and contraction of the iris. He also described the cataract operation.
In 1050 A.D. at Baghdad, Ali Ibn-Isa (Jesu Haly) wrote the classic book on ophthalmology, Tathkirat Al-Kahhalin (A Note for the Oculists). As stated by Cunistan (1921), it is the oldest book in its original language on diseases of the eye. In a clear and logical style, the author described trachoma, conjunctivitis, and cataract, and prescribed treatment (Keys 1971). Avicenna described the six extrinsic muscles of the eyeball.
In the thirteenth century, Ibn Abu-Al-Kawafer wrote a book on therapeutic ophthalmology entitled "Natigat-El-Fikr fi Ilag Amrad El-Bassar" (Conclusions from Expelience on Treatment of Diseases of the Eye). According to Kahil (1929) is one of several textbooks of ophthalmology considered to be superior to any written in Europe up to the eighteenth century.