Modern cases of shell shock
Although the term "shell shocked" is typically used in discussion of WWI to describe early forms of PTSD, its high-impact explosives-related nature provides modern applications as well. During their deployment in Iraq and Afghanistan, approximately 380,000 U.S. troops, about 19% of those deployed, were estimated to have sustained brain injuries from explosive weapons and devices. This prompted the U.S. Defense Advanced Research Projects Agency (DARPA) to open up a $10 million study of the blast effects on the human brain. The study revealed that, while the brain remains initially intact immediately after low level blast effects, the chronic inflammation afterwards is what ultimately leads to many cases of shell shock and PTSD. See also
Combat stress reaction

References
Sources
Coulthart, Ross. The Lost Diggers, Sydney: HarperCollins Publishers, 2012. ISBN 978-0732294618
Jones, E, Fear, N and Wessely, S. "Shell Shock and Mild Traumatic Brain Injury:  A Historical Review". Am J Psychiatry 2007; 164:1641–1645
Hochschild, Adam. To End all Wars – a story of loyalty and rebellion, 1914–1918 Mariner Books, Houghton, Mifflin Harcourt, Boston & New York, 2011. ISBN 978-0547750316
Horrocks, J. (2018). The limits of endurance: Shell shock and dissent in World War one. The Journal of New Zealand Studies, (NS27). https://doi.org/10.26686/jnzs.v0ins27.5175
Leese, Peter. Shell Shock. Traumatic Neurosis and the British Soldiers of the First World War, Palgrave Macmillan, 2014. ISBN 978-1137453372. MacLeod, A. D. (2004). "Shell shock, Gordon Holmes and the Great War". Journal of the Royal Society of Medicine. 97 (2): 86–89. doi:10.1177/014107680409700215. PMC 1079301. PMID 14749410. Myers, C.S. "A contribution to the study of shell shock".
Additional gradients are formed within the retina. This spatial distribution may aid in proper targeting of RGC axons that function to establish the retinotopic map. Blood supply
The retina is stratified into distinct layers, each containing specific cell types or cellular compartments that have metabolisms with different nutritional requirements. To satisfy these requirements, the ophthalmic artery bifurcates and supplies the retina via two distinct vascular networks: the choroidal network, which supplies the choroid and the outer retina, and the retinal network, which supplies the retinas inner layer. Circulatory mechanisms
At first glance, one may think that the vertebrate retina is "wired wrongly" or "badly designed"; but in fact, the retina could not function if it were not inverted. The photoreceptor layer must be embedded in the retinal pigment epithelium (RPE), which performs at least seven vital functions, one of the most obvious being to supply oxygen and other necessary nutrients needed for the photoreceptors to function. These nutrients include glucose, fatty acids, and retinal. The mammalian photoreceptor amplification process uses large quantities energy for vision in photopic conditions (requiring less under scotopic conditions) and, thus, requires the large supply nutrients supplied by the blood vessels in the choroid, which lies beyond the RPE. The choroid supplies about 75% of these nutrients to the retina and the retinal vasculature only 25%.When light strikes 11-cis-retinal (in the disks in the rods and cones), 11-cis-retinal changes to all-trans-retinal which then triggers changes in the opsins.