Blind spot

A blind spot, also known as a scotoma, is an obscuration of the visual field. A particular blind spot known as  the blind spot, or physiological blind spot, is the specific scotoma in the visual field that corresponds to the lack of light-detecting photoreceptor cells on the optic disc. Since there are no cells to detect light on the optic disc, a part of the field of vision is not perceived. The brain fills in with surrounding detail and with information from the other eye, so the blind spot is not normally perceived. Although all vertebrates have this blind spot, cephalopod eyes which are only superficially similar do not.

{| class="wikitable" rules="none" ! colspan="5" style="border:solid 1px #AAAAAA;" | Try it yourself |- | colspan="5" height="50px" | |- | align="center" style="font-size: 0.7cm;"| A | align="right" style="font-size: 0.7cm;"| O | style="width: 10cm;" | | align="left" style="font-size: 0.7cm;" | X | |- | colspan="5" height="50px" | |- | colspan="5" style="border:solid 1px #AAAAAA;" | Instructions: Your face should be very close to the screen. Cover right eye and focus the left eye on the X. Now slowly move away from the screen. The O will disappear, while the A which is further to the left is still visible|}