Inclusion Criteria:
* 1\. Fully understand the purpose and requirements of this trial, voluntarily participate in the clinical trial, sign the informed consent form, and be able to complete the whole trial processes as required by the protocol;
* 2\. Patients with clinical diagnosis of Bietti's crystalline dystrophy (BCD) (age ≥ 18 years) (including the critical value, and the age is based on the time of signing the informed consent form);
* 3\. Genetic test confirmed to carry two pathogenic variants of CYP4V2 and carry no pathogenic mutations of other ophthalmic genetic diseases;
* 4\. The study eye must meet the following requirements: Best-corrected visual acuity between 2.3 LogMAR and 0.5 LogMAR (including 2.3 LogMAR and 0.5 LogMAR).
Exclusion Criteria:
* 1\. Subjects with insufficient viable retinal cells, or macular retinal less than 100 μm thick;
* 2\. Pre-existing eye conditions in the study eye that the investigator determines could interfere with ocular evaluation, preclude surgery, interfere with interpretation of study endpoints or pose surgical complications;
* 3\. The study eye has been treated with the following intraocular procedures: retinal detachment surgery, vitrectomy;
* 4\. The study eye has been treated with other drugs within 3 months that could affect the evaluation of the investigational drug (such as ranibizumab, bevacizumab, aflibercept, conbercept);
* 5\. Currently taking or may require systemic medications that can cause ocular toxicity, such as psoralen, risedronate, or tamoxifen;
* 6\. Those with the following laboratory abnormalities which are clinically significant:
* Liver function: chronic liver disease, ALT increased \> 2 times the upper limit of normal;
* Hypertension, mean SBP ≥ 160 mmHg or mean DBP ≥ 100 mmHg;
* Coagulation function (prothrombin time ≥ upper limit of normal (3 seconds' longer), activated partial thromboplastin time ≥ upper limit of normal (10 seconds' longer));
* Serum virology test: Active hepatitis B, hepatitis C virus antibody (HCV-Ab), human immunodeficiency virus antibody (HIV-Ab) or syphilis antibody positive;
* 7\. Patients with rAAV8 neutralizing antibody titer ≥ 1:1000;
* 8\. Complicating systemic diseases (such as medical conditions causing immunosuppression) that would preclude the gene transfer, ocular surgery and drug in vivo activity;
* 9\. Known drug allergy to the drug planned to be used in the study;
* 10\. Patients who cannot communicate or cooperate with medical staff due to neurological, mental illness or language disorder, which affects patient compliance;
* 11\. Treatment of either eye with gene therapy drugs for BCD and other ocular diseases, including but not limited to other viral vector gene therapies, mRNA therapy, etc.;
* 12\. Has or has had a systemic immune-compromising disease;
* 13\. Subjects of reproductive age without any effective contraception and female subjects who have tested positive for pregnancy or are lactating at screening or baseline;
* 14\. A condition that, in the opinion of the investigator, would preclude participation in the study.
