Ali ibn Isa

Full name: 
ʿAlī ibn ʿĪsā al-Kahhal
Arabic name: 
علي بن عيسى الكحال

'Ali ibn 'Isa was a notable oculist (kahhal) of Baghdad whose life falls in the first half of the 11th century. His main work is Tadkirat Al-kahhalin (Manual for Oculists or Note-book of the Oculists). It is the classical handbook of Muslim ophthalmology, translated once into Hebrew and twice into Latin, and was printed with the title of Tractatus de oculis Jesu Halis in Venice in 1497, 1499 and 1500. It is the oldest Muslim work on ophthalmology that is complete and survives in the original state. It would be of interest to the modern reader to quote Elgood on the three sections of the Tadkirat:

`The first part is devoted to anatomy, the second to the external diseases of the eye, and the third part to internal diseases of the eye which are not visible upon inspection. This last section is perhaps the most interesting from a modern point of view, for it shows the very definite limitations of Greek and Arab ophthalmology. The ophthalmoscope and the power of seeing the retina have revolutionized ophthalmologic practice. When Ali speaks of internal diseases of the eye, he literally means diseases confined to the eye. The possibility of first diagnosing diabetes, kidney disease and cerebral tumour in the ophthalmic consulting room is not conceived of by the oculists of those times. The nearest approach that Ali makes to the modern conception of eye disease as a manifestation of general disease is when he urges the practitioner to realize that defective vision may be due to a disease of the stomach or brain just as much as to an incipient cataract. And with that he leaves the question.'

Despite this limitation which was common to all oculists of Ibn Isa's day and which continued for many centuries later, his Tadkirat, passed over to Europe and became the foundation of Western practice. It has been used on a large scale by later Muslim oculists until the present day, both for the practical and theoretical portions, and whole chapters have frequently been quoted. A German translation of the Manual for oculists' based on the Muslim manuscripts can be found.