Visual impairment in the aging population may be brought about by localized pathological change or it may be associated with systemic disease. Localized ocular disorders include three of the commonest causes of visual loss in the elderly, namely cataract, glaucoma and age-related macular degeneration. Systemic diseases, with associated ocular involvement which may progress to blindness, include diabetes, hypertension and hyperlipidaemia, which predispose to retinal vascular occlusion. Visual function may also be affected by various autoimmune disorders (e.g. rheumatoid arthritis), cerebrovascular disease, intraocular or intracranial tumours (primary or metastatic), as well as by infectious agents (herpes zoster ophthalmicus) and drugs (steroids).