Editing Retinopathy (section)

=== Non-proliferative retinopathy ===
Non-proliferative retinopathy is often caused by direct damage or remodeling of the small blood vessels supplying the retina.<ref name=":1" /> Many common causes of non-proliferative damage include [[hypertensive retinopathy]], [[retinopathy of prematurity]], [[radiation retinopathy]], [[solar retinopathy]], [[sickle cell retinopathy]], and anemic retinopathy<ref>{{cite journal | vauthors = Carraro MC, Rossetti L, Gerli GC | title = Prevalence of retinopathy in patients with anemia or thrombocytopenia | journal = European Journal of Haematology | volume = 67 | issue = 4 | pages = 238–244 | date = October 2001 | pmid = 11860445 | doi = 10.1034/j.1600-0609.2001.00539.x | s2cid = 20875243 }}</ref> (including secondary to [[pernicious anemia|vitamin B12 deficiency]]<ref>{{cite journal | vauthors = Jojo V, Singh P | title = The eye: A lifesaver! An unusual case of Anemic Retinopathy secondary to Malnutrition and its recovery | journal = Journal of Family Medicine and Primary Care | volume = 9 | issue = 8 | pages = 4421–4424 | date = August 2020 | pmid = 33110874 | pmc = 7586514 | doi = 10.4103/jfmpc.jfmpc_577_20 | doi-access = free }}</ref>).

There are three main mechanisms of damage in non-proliferative retinopathy: blood vessel damage or remodeling, direct retinal damage, or occlusion of the blood vessels. The first mechanism is indirect damage by altering the blood vessels that supply the retina. In the case of [[hypertension]], high pressures in the system cause the walls of the artery to thicken, which effectively reduces the amount of blood flow to the retina.<ref name=":1" /> This reduction in flow causes tissue [[ischemia]] leading to damage. [[Atherosclerosis]], or hardening and narrowing of blood vessels, also reduces flow to the retina. The second mechanism is direct damage to the retina usually caused by [[free radicals]] that causes [[Oxidative stress|oxidative damage]] to the retina itself.<ref>Youseff PN, Sheibani N, Albert DM. Retinal light toxicity. Eye (Lond). 2011; 25(1):1–14.</ref> Radiation, solar retinopathy, and retinopathy of prematurity fall under this category. The third common mechanism is occlusion of blood flow. This can be caused by either physically blocking the vessels of the retinal artery branches or causing the arteries to narrow.<ref name=":2" /> Again, the result is reduced blood flow to the retina causing tissue damage. Sickle cell disease compromises blood flow by causing blood to sludge, or thicken and flow slowly, through the retinal arteries. Other disorders that cause [[hyperviscosity syndrome]] may also cause blood sludging. Lastly, clots or [[Retinal artery occlusion|central artery thrombosis]] directly blocks flow to the retina causing the cells to die.