The patient was a 56-year-old male. Because of blurred vision in his left eye for 3 days, he went to the Affiliated Optometry Hospital of Wenzhou Medical University. Previous history of hypertension for 10 years, controlled with medication (specificity unknown). Eye examination: visual acuity was 1.0 for the right eye and 0.1 for the left eye; IOP was 17.7 mmHg (1 mmHg =0.133 kPa) in the right eye and 15.7 mmHg in the left eye; The conjunctiva of both eyes is not congested, the cornea is transparent, the anterior chamber is clear and deep, the pupil is round, and the lens is mildly opaque; No obvious abnormalities were observed in the right eye; Vitreous hemorrhage in the left eye, neovascularization in the optic disc and retina, and laser photocoagulation plaque above the retina (Quintessence Picture 1In a). The results of fluorescein fundus angiography in the left eye are shown in B in Essence Picture 1. Clinical diagnosis: branch retinal vein occlusion in the left eye.