Advances in noninvasive imaging technologies such as optical coherence tomography (OCT) and OCT angiography (OCTA) have revolutionized the use of ocular biomarkers for early disease detection, monitoring, and therapeutic assessment. Accurate interpretation of these biomarkers relies on well-established normative data to distinguish pathology from normal variation. Biomarkers now play a central role in managing age-related macular degeneration (AMD), diabetic retinopathy, glaucoma, and systemic diseases like Alzheimer’s and cardiovascular disease. Retinal and choroidal structural features such as nerve fiber layer thickness, drusen volume, vascular caliber, and fluid accumulation can provide objective insights into ocular and systemic health. Functional measures, including electroretinogram (ERG) and saccadic eye movement latency, further enhance diagnostic capability. Ocular biomarkers also offer emerging potential for detecting early signs of neurodegeneration and systemic inflammation. This chapter outlines key retinal biomarker parameters and detection methods, emphasizing their growing impact in precision ophthalmology and translational vision science.