Abu al-Qasim Ammar ibn Ali al-Mawsili (Arabic: عمار الموصلي) was an important eleventh-century Arab Muslim ophthalmologist. Despite little being known about his life or education, he has been described as the most original of all Arab oculists. As his nisba indicates, Ammar was born in Mosul, and later moved to Egypt, where he settled during the reign of the Fatimid caliph al-Hakim bi-Amr Allah, to whom he wrote his only composition, Kitāb al-muntakhab fī ilm al-ayn (“The book of choice in ophthalmology”). Regarding his invention he wrote the following: