This project integrates multimodal eye data (CFP, OCT, OCTA) from 50,000 cases, brain MR data from 150,000 cases, and ICD diagnoses, medical orders, and test results from an eye-brain paired cohort of 8,000 cases to construct an eye-brain cross-modal mapping model and an eye-brain-systemic disease association model. It aims to clarify the quantitative associations between multimodal ocular features and brain structural and vascular characteristics as well as systemic disease ICD diagnoses, thereby uncovering the cross-organ and cross-modal linkage mechanisms between the eye and brain. Ultimately, it seeks to achieve mapping and prediction of brain imaging features based on ocular data, enable ocular-based diagnosis and prediction of various diseases, and contribute significantly to early disease screening, risk stratification, and optimization of clinical diagnosis and treatment.

Inclusion Criteria:

• Eye data: Images must meet quality standards (no significant artifacts, key structures clearly visible), with complete examination records (including examination date and device model).
• Brain data: MR images must be free of motion artifacts, with complete sequences (at least including T1-weighted imaging and MRA), and reports must confirm no technical issues.
• Eye-brain paired cohort: Must contain at least one type of eye image (including CFP, OCT, or OCTA) along with brain MR data, and be linkable to a unique identifier and clinical information in the database
• Clinical data: Clinical information (such as core biochemical indicators, demographic information, and necessary questionnaire items) must have a missing rate ≤30%, with standardized and clear ICD diagnostic codes, complete laboratory test data, and medical order information (including medication or follow-up recommendations)
• Prior to initial inclusion in the study, participants must have no history of severe organic diseases (including non-curable or end-stage malignancies, severe heart failure (NYHA Class III-IV), end-stage renal disease (CKD Stage 5), decompensated cirrhosis, or significant functional impairment due to severe cerebrovascular disease sequelae, etc.).

Exclusion Criteria:

• Ocular examinations in which key features cannot be identified due to conditions such as cataracts or vitreous hemorrhage brain MR images deemed unacceptable in quality due to factors such as metal implants
• Clinical information (including core biochemical indicators, demographic details, essential questionnaire items, etc.) with a missing rate exceeding 30%
• Individuals who are pregnant or lactating, those with ocular trauma, congenital ocular malformations, or severe organic diseases.

(1) Ophthalmic Data Cohort: Patients and health check-up participants who underwent CFP , OCT or OCTA examinations at Beijing Friendship Hospital, Capital Medical University, from January 2009 to September 2025.(2) Cerebral Data Cohort: Patients and health check-up participants who underwent cerebral MR (Magnetic Resonance) examinations at the same hospital during the corresponding period.(3) Oculo-Cerebral Matched Cohort: Individuals from Beijing Friendship Hospital, Capital Medical University and the UK Biobank (UKB) database who had any of the above ophthalmic imaging examinations, plus cerebral MR scans, and could be matched with complete clinical information.(4) Clinical Correlation Cohort: Individuals from the above cohorts who had complete ICD (International Classification of Diseases) diagnoses, laboratory test results (including blood glucose, blood lipids, uric acid, etc.) and medical order records at Beijing Friendship Hospital, Capital Medical University.