Peripheral vision is obtained by means of the nerve cells situated outside the center or the macula of the retina. These nerve cells allow the eyes to perceive objects and other movements outside the central visual field and the direct line of vision. While looking steadily towards a specific object or path the eyes gaze on the central visual field or the most important object of focus. However, other objects or non-central objects seem outside the region of the central visual field and can be perceived by the eyes. This vision is recognized as the peripheral or side vision.
Peripheral vision can be distinguished in three sorts, namely, far peripheral, mid-peripheral and close to peripheral. Far-peripheral vision aids in seeing the objects existing at the edges of the visual field whereas mid-peripheral refers to vision in the middle of the visual field. Near peripheral, also recognized as "paracentral" vision, exists pretty much next or adjacent to the central region of gaze.
The researches confirm of human beings have weaker peripheral vision as compared to animals, especially when it comes to distinguish shapes and colors. This is due to a greater density of the receptor cells at the center of the retina, which becomes lowest at the edges. In addition, the rod cells and the cone cells, forming the two forms of receptor cells, are not able to distinguish colors. They concentrate mainly on the center of the retina, the macula. The peripheral vision assists in detecting motions by means of the rod cells and is in most cases stronger at night or in the dark when faced with scarcity of colors and light, which reduces the functionality of the cone cells.
The loss of peripheral vision could occur due to many ocular or neurological disorders. Some of the most frequent causes of losing peripheral vision might possibly include things like transient migraine, glaucoma, stroke, ischemic optic neuropathy, branch retinal vein and branch retinal artery occlusion. On the other hand, some of the uncommon and rare causes may be pituitary tumors, brain tumors and aneurysms, and gyrate atrophy, to name a couple of.
