In patients with diabetes and hypertension, after a thorough examination by an internist, he is also asked to go to the ophthalmology department for fundus examination. What is the relationship between diabetes, hypertension and fundus? Diabetes mellitus is an endocrine metabolic disease that can affect all organs of the body. It can cause cataract, retinopathy, temporary refractive error and extraocular muscle paralysis, among which retinopathy is the most common. The incidence of fundus lesions increases gradually with the duration of diabetes. According to domestic reports, the prevalence of fundus changes is 38%-39% for those with a disease duration of less than 5 years, 50%-56.7% for those with a disease duration of 5-10 years, and 69%-90% for those with a disease duration of more than 10 years. Early fundus examination reveals scattered microangiomas and small punctate or patchy hemorrhages in the posterior pole of the retina, and filled and dilated retinal veins with mild tortuosity. As the disease progresses, in addition to microangiomas and punctate or flaky hemorrhages, white or yellow-white exudates appear at the same time, and the lesions often spread to the macula and affect vision. With further progression, extensive neovascularization appears on the retina and optic papilla with proliferation of connective tissue, recurrent retinal hemorrhages, and increased cotton wool exudates, severely impairing vision. In advanced or severe cases, massive vitreous hemorrhage can occur repeatedly, and if the hemorrhage cannot be completely absorbed, it can produce mechanized cords that adhere to the retina, causing proliferative vitreoretinopathy, and the proliferative cords can pull the retina and cause retinal detachment, eventually leading to blindness. In patients with hypertension, the long-term persistent elevation of blood pressure can cause some pathological changes in the retina. Early spasm of the small retinal arteries is seen as a thinning and reflective enhancement. If the spasm persists, it may develop into atherosclerosis, with indentation at the arteriovenous crossings, and in severe cases, copper or silver wire-like arteries may appear. If the disease progresses and blood pressure increases sharply, retinal edema, hemorrhage and exudation may occur, and further development of increased intracranial pressure may be combined with optic papilloedema. Thus, fundus examination of diabetes and hypertension provides an extremely important reference basis for early diagnosis, treatment and prognosis of the disease.