In the Blind Spot
by Elizabeth McTaggart
Title
In the Blind Spot
Artist
Elizabeth McTaggart
Medium
Digital Art - Fractal Art
Description
In the Blind Spot
The eye's blind spot is a result of the absence of photoreceptor's in the area of the retina where the optic nerve leaves the eye.
Each human optic nerve contains between 770,000 and 1.7 million nerve fibers, which are axons of the retinal ganglion cells of one retina. In the fovea, which has high acuity, these ganglion cells connect to as few as 5 photoreceptor cells; in other areas of retina, they connect to many thousand photoreceptor's.
Damage to the optic nerve typically causes permanent and potentially severe loss of vision, as well as an abnormal pupillary reflex, which is diagnostically important. The type of visual field loss will depend on which portions of the optic nerve were damaged. In general:
Damage proximal to the optic chiasm causes loss of vision in the visual field of the same side only.
Damage in the chiasm causes loss of vision laterally in both visual fields (bitemporal hemianopsia). It may occur in large pituitary adenomata.
Damage distal to the chiasm causes loss of vision in one eye but affecting both visual fields: The visual field affected is located on the opposite side of the lesion.
Injury to the optic nerve can be the result of congenital or inheritable problems like Leber's Hereditary Optic Neuropathy, glaucoma, trauma, toxicity, inflammation, ischemia, infection (very rarely), or compression from tumors or aneurysms. By far, the three most common injuries to the optic nerve are from glaucoma, optic neuritis (especially in those younger than 50 years of age), and anterior ischemic optic neuropathy (usually in those older than 50).
[source: Wikipedia]
Uploaded
February 17th, 2013
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Comments (16)
Elizabeth McTaggart
Thank you so much for the visit, compliment and v/f, Marcia! I appreciate it!! :)
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