Double Opening

The pages shown here are from a thirteenth-century copy of Memorandum for Oculists (Takhkirat al-kahhalin) of Ali Ibn Isa. Ali ibn Isa al-Kahhal was a practising eye specialist living in late 10th-century Baghdad, where he wrote this influential textbook. It explores the means by which eyes can see, and catalogues diseases of the eye and their treatment. On these pages he discusses seeing at a distance and up close. His work was translated into many languages and published in Latin in 1497.