His acclaimed treatise on optics, namely "Kitab al-Manazir" was translated into Latin under the title "Opticae Thesaurus Alhazeni" in 1270 by Witelo. Afterwards, it was published by Frederick Risner at Basel in 1572. According to Ibn al-Haytham, "It is not a ray leaving the eyes that causes sight! It is far more the form of the perceived object that radiates onto the eye and is converted by its transparent body."
Jafar Sadik further recommended for an invention of an instrument to watch an object of a remote distance 50 times nearer. Hence, the European scientist, Roger Bacon (1220-1292) had also proposed for such instrument, bringing an object 50 times near to our sight. Later on, the Italian scientist Gailileo (1564-1642) was destined to invent the suggestive instrument, that is, telescope in 1610; whose functions absolutely based on the theory of Jafar Sadik, bringing an object visible 50 times closer to its actual distance.