The discoveries of Ibnul Haitham had a great impact on the human intellectual heritage in general. What concerns us most is his scientific specialization is his book “Visions”. It was encountered a revolution in the world of Optics because Ibnul Haitham did not adopt Ptolemy’s theories to explain it or even correct it. Instead he rejected a number of his Optics theories after concluding several new theories that were seeds for the modern Optics.
Ptolemy, as we pointed out, claimed that vision happens when rays are emitted from the eyes and hit an object. Then following scientists adopted this theory. Then when Ibnul Haitham came, he blew out this theory in his book “Visions”. He showed that vision happens when rays are reflected off the object observed and into the eyes of the observer. This conclusion was reached after carrying out a set of experiments that showed that light rays travel in straight lines within a homogeneous medium:)