**Background:** With nearly a quarter of Americans projected to be older than 65 by 2030 and the number of Americans 85 and older expected to triple by 2060, understanding age-related ocular changes is increasingly important. This narrative review summarizes the literature on normal anatomical and functional changes in the aging eye and discusses the role of oxidative stress in the three most common age-related ocular pathologies: cataracts, glaucoma, and age-related macular degeneration (AMD).
**Methods:** The authors present a review of the literature covering both anterior and posterior segment changes. Anterior segment changes discussed include eyelids and lacrimal glands (dermatochalasis, blepharoptosis, dry eye), sclera (increased stiffness and rigidity), cornea (endothelial cell loss, Fuchs' dystrophy, astigmatism shift, arcus senilis, immunocompromise), trabecular meshwork (47% decline in cell number over 81 years, increased outflow resistance), ciliary body (morphological changes), and crystalline lens (yellowing, 450-fold elevation in stiffness, presbyopia). Posterior segment changes include vitreous humor (liquefaction, posterior vitreous detachment with up to 14% complicated by retinal tear), retina and RPE (depletion of retinal ganglion cells and photoreceptors with greater rod than cone loss, lipofuscin accumulation, melanin decline), choroid (reduced thickness, vessel volume, and choriocapillaris density), macula and fovea (Bruch's membrane thickening and calcification, drusen deposition), and optic nerve (reduced nerve fiber density and neural rim volume).
**Key Results:** Cataract prevalence in the United States was 15.45% in individuals aged 60–64 years and 68.30% in those aged 80 years or older. The global prevalence of glaucoma is expected to reach 111.8 million by 2040, with greater burden in Asia and Africa. AMD national prevalence based on 2005–2008 NHANES data is 6.5%, with global prevalence projected to reach 288 million by 2040. The Antioxidants for the Prevention of Cataracts (APC) study found no significant difference in cataract surgery rates between those receiving vitamin C, vitamin E, and beta carotene supplementation versus placebo over 15 years. The AREDS2 follow-up study showed significantly lower risk of late AMD development with lutein/zeaxanthin supplementation. A randomized controlled trial adding docosahexaenoic acid, lutein, zeaxanthin, resveratrol, and hydroxytyrosol to the original ARED formula reduced inflammatory cytokine levels in unilateral wet AMD patients but showed no significant improvement in visual acuity after one year. Macuprev® supplementation increased amplitude density on multifocal electroretinogram at the central macular area in intermediate AMD patients.
**Clinical Implications:** Oxidative stress is a central mechanism in age-related ocular pathology, driven by accumulation of reactive oxygen species and diminished antioxidant levels. In cataracts, ROS cause protein modifications (oxidation, deamidation, glycation), DNA damage, lipid peroxidation, and antioxidant depletion. In glaucoma, elevated oxidative stress markers (protein carbonyls, advanced glycation end products, malondialdehyde) are found in aqueous humor, with mitochondrial dysfunction contributing to trabecular meshwork cell loss and increased intraocular pressure. In AMD, ROS from oxygen consumption, light exposure, and RPE phagocytosis drive drusen formation, complement system dysfunction, and choroidal neovascularization. Nutritional interventions show promise: lutein/zeaxanthin for AMD prevention, and various supplements (nicotinamide, flavonoids, resveratrol, ginkgo biloba) for reducing retinal ganglion cell loss and improving ocular blood flow in glaucoma. Understanding these oxidative mechanisms is essential for developing targeted therapies to address the growing burden of age-related eye disease.