Safety Study of rAAV2/8-hCYP4V2 in Patients With Bietti's Crystalline Dystrophy (BCD)

Inclusion Criteria: * 1\) Age ≥ 18 years old at the time of informed consent ; * 2\) Patients with a clinical diagnosis of Bietti's crystalline dystrophy (BCD); * 3\) Genetic test confirmed to carry two pathogenic variants of CYP4V2; * 4\) Meet the following target eye selection criteria： Best corrected visual acuity between 2.3 LogMAR and 0.5 LogMAR (including 2.3 LogMAR and 0.5 LogMAR, equivalent to Snellen visual acuity of hand move to 20/63); No refractive media clouding affecting fundus examination, visual examination and retinal function examination; The eye with the poorer visual acuity of the two eyes of the subject is the target eye. Note: For all subjects, only one eye will be used as the "target eye". If both eyes meet the inclusion criteria and the visual acuity is comparable, the target eye will be determined medically by the investigator. * 5\) Agree to take effective contraceptive measures from the beginning of the study to 2 year after the administration; * 6\) Voluntarily participate in this clinical trial and have signed the informed consent form. Exclusion Criteria: * 1\) Patients lack sufficient retinal photoreceptors, retinal photoreceptors less than 1 optic disc area or retinal thickness less than 100 μm in the macula； * 2\) Existing or pre-existing of choroidal neovascular (CNV) lesions that were secondary to BCD, or other eye conditions interfering（ (e.g., high refractive error, retinal vasculitis, etc.) ） that may prevent surgery or interfere with …