How can eye specialists determine the difference between diabetic and hypertensive retinopathy?

Exam and testing: Dilated fundus exam--diabetic and hypertensive retinopathy typically have different appearances, however they can appear similar with bleeding and ischemic areas of the retina. Areas requiring treatment to save vision (other than improving the underlying disease) can be found using imaging and angiogram diagnostic tests.

See below: Though they can sometimes look similar, an eye doctor (especially a retina specialist), can tell the difference by doing a dilated retinal exam sometimes also with ancillary testing like Fluorescein angiography and optical coherence tomography.