The Retina

<p>May 30, 2015 06:38 PM</p>

<p>from U Penn &nbsp;online anatomy from 1982 book.</p>

<p>layer at the top of the photomicrograph is the rods and cones. &nbsp;(RPE not shown)</p>

<p>in most primates the retina is about &nbsp;200 to 250 microns thick.</p>

<p>outermost layer is &nbsp;retinal pigmented epithelium &nbsp;(RPE cells in humans) &nbsp;that support photopigment regeneration. &nbsp;then</p>

<p>rod and cone layer &nbsp;(outer segments of rod and cones)</p>

<p>next the outer limiting membrane &nbsp;then the</p>

<p>ONL = cell bodies of rods and cones; &nbsp;then
OPL = outer plexiform layer: &nbsp;rod and cone axons, horizontal cell dendrites, and bipolar dendrites &nbsp;(that's a wiring layer)</p>

<p>INL = inner nuclear layer: &nbsp;nuclei of horizontal, bipolar, and amacrine cells then</p>

<p>
IPL = &nbsp;inner plexiform layer &nbsp;(axons of bipolar and amacrines and and dendrites of ganglion cells.</p>

<p>then GCL &nbsp;ganglion cell layer &nbsp;(nuclei of the ganglion cells then</p>

<p>layer of optic nerve fibers &nbsp;from &nbsp;RGCs that leave the eyeball at the optic disk. (blind spot)</p>

<p>central island is &nbsp;0.17 to 0.24 degrees &nbsp;(50 to 75 microns)
the longest cones and rod-free &nbsp;(and no blue cones)</p>

<p>foveola is 1.4 degrees &nbsp;400 microns in diameter, the flat pit of the fovea; &nbsp;25,000 cones
the blood vessel-free area is 1.4 to 2.3 degree;
fovea is 5.2 degrees and 1.5 mm &nbsp;... about 110,000 to 115,000 cones.</p>

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