[1] Retinopathy often refers to retinal vascular disease, or damage to the retina caused by abnormal blood flow.

[2] Age-related macular degeneration is technically included under the umbrella term retinopathy but is often discussed as a separate entity.

[5] It accounts for about 5% of blindness worldwide and is designated a priority eye disease by the World Health Organization.

When there is an unusually high or fast rate of angiogenesis, there is an overgrowth of blood vessels called neovascularization.

Non-proliferative retinopathy is often caused by direct damage or remodeling of the small blood vessels supplying 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.

Lastly, clots or central artery thrombosis directly blocks flow to the retina causing the cells to die.

These pathologically overgrown blood vessels are often fragile, weak, and ineffective at perfusing the retinal tissues.

[13] These weak, fragile vessels are also often leaky, allowing fluids, protein, and other debris to leach out into the retina.

This makes proliferative types of retinopathy more risky since vessel hemorrhaging often leads to vision loss and blindness.

Physical exertion like weight lifting and aerobic exercise, coughing, sneezing, straining at stool, vomiting, sexual intercourse, blowing up balloons, blowing musical instruments, cardiopulmonary resuscitation or compression injuries may cause valsalva retinopathy.

Evidence shows that laser therapy is generally safe and improves visual symptoms in sickle cell and diabetic retinopathy.

Vascular endothelial growth factor (VEGF) seems to play a vital role in promoting neovascularization.

Using anti-VEGF drugs (antibodies to sequester the growth factor), research have shown significant reduction in the extent of vessel outgrowth.

Low quality evidence supports the use of anti-VEGF antibodies, such as bevacizumab or pegaptanib which seems to improve outcomes when used in conjunction with laser therapy to treat retinopathy of prematurity, longer term systemic effects are not known however.

Use of anti-VEGF drugs did not appear to improve outcomes in a clinically significant way when compared to standard laser therapy for diabetic retinopathy.