This chapter explores the influence of genetic and ethnic factors on ocular anatomy, physiology, and disease susceptibility. It highlights how inherited traits and population-specific genetic variations shape eye characteristics such as refractive errors, corneal thickness, axial length, intraocular pressure, optic nerve structure, and retinal anatomy. Key differences include a higher prevalence of myopia in East Asians, increased glaucoma risk in individuals of African descent, and greater susceptibility to age-related macular degeneration (AMD) in Caucasians. Ethnic variations also affect corneal curvature, pupil size, and macular thickness. Understanding these distinctions enhances diagnostic accuracy and supports more personalized, population-specific approaches to eye care and disease management.