The reasons why the patient’s black eye becomes smaller are as follows: a. The border of the corneoscleral rim becomes blurred: clinically, it is more common mostly due to inflammation, or prolonged lack of oxygen in the cornea. The vascular network around the corneoscleral rim expands or even proliferates, and enters the corneal rim, so that the border becomes blurred, there is a local gradually become infiltrated, edema, etc., the patient will have eye pain, photophobia, tearing, vision loss, etc. Second, the elderly ring: in the peripheral part of the cornea there is a white ring-like lipid degeneration, mostly due to low-density lipoprotein deposition and constituted, the elderly are more common, and atherosclerosis, corneal rim vascular network permeability enhancement related. Third, congenital small cornea: Although relatively rare, it also forms a small black eye, generally refers to the diameter of the cornea is less than 10mm, the cornea is mostly flat, accompanied by other abnormal symptoms such as hyperopia, is a familial genetic disease.