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 the interpretation of the study endpoint; * 3\) Prior use of medicines which may affect the experimental observation within the 6 months before screening (such as ranibizumab, bevacizumab, aflibercept, conbercept)； * 4\) Prior intraocular surgery in the target eye (e.g. PDT, pars plana vitrectomy, retinal laser therapy ) * 5\) Currently taking or may require systemic medications that can cause ocular toxicity, such as psoralen, risedronate, or tamoxifen； * 6\) Allergic constitution (such as those who are allergic to two or more drugs and foods); * 7\) Abnormal physical examination, vital signs, laboratory tests (blood routine, urine routine, blood biochemistry, coagulation function, immunological examination, female blood pregnancy), 12-lead ECG, X-ray chest radiograph findings with any clinically significant abnormality, and where participation in this study may increase the subject's risk or interfere with data interpretation as assessed by the investigator； * 8\) Having any past or present medical history that may affect the safety of the trial or the in vivo process of the drug, especially the medical history of cardiovascular, hepatic, renal, endocrine, gastrointestinal, pulmonary, neurological, hematological, oncologic, immunological or metabolic disorders and others that are thought clinically significant by the investigator； * 9\) Participation in any medicine or medical device clinical trials within 3 months prior to enrollment;; * 10\) Neutralizing antibodies to rAAV\> 1:1000 by immunologic test; * 11\) For females in pregnancy or lactation period; * 12)Carrying other ophthalmic pathogenic mutations * 13\) Any other conditions which leads the investigator to determine the participant is unsuitable for this study.