After a thorough examination by an internist, a patient with diabetes and hypertension is also asked to have his fundus examined by an ophthalmologist. What is the relationship between diabetes mellitus, hypertension and fundus? Diabetes 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 gradually increases 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 funduscopic 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, the lesions often affect vision by spreading to the macula. Further progression results in extensive neovascularization of the retina and optic papilla with proliferation of connective tissue, recurrent retinal hemorrhages, and severe impairment of vision. In advanced cases, massive vitreous hemorrhage may occur repeatedly, causing proliferative vitreoretinopathy and retinal detachment caused by proliferating cords pulling on the retina, 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.