A Study on the Development of Vision Theory in Scientist's Works in Eslamic Era

Islamic-Iranian culture which not only save the legacy of Greece from extinction and brought order brought order to it and transformed it to Europe, but made the bases of many sciences which are owned to translations conduced by scientists such as Hanin Ibn Eshagh and Ibn Masouyeh. One of the fields of these sciences is the process of vision whose honor of development and completeness is for scientists in Islamic era especially Ibn Heisam. Knowledge, art of vision and ophthalmology were not so developed among the Roman and the Greek. Scientists of Islamic era took what they know in this regard and completed it in a limited framework but successfully. Also, one of the other discussions in the works of Islamic era was the focus on far sightedness and near sightedness which, the scientists believed, was a phenomenon entitled “the watching soul” and it went to the center of brain by a hollow neuron and came back again. Four basic factors caused far sightedness and near sightedness: The excess density of the watching soul, its excessive clarity, its decrease and increase. The author of the present article tried to have a look at the process of vision and to present it in a preliminary way in the works of Greek physicians and the process of its development in the works of Islamic era, intends to deal with the works of some scientists such as Ibn Heisam. Also, the feature of vision in far sightedness and near sightedness is among the discussions which was posed in Islamic era for the first time.