As the eye ages, certain changes occur that may affect vision. Presbyopia is corrected by the use of reading glasses. Cataracts are common and vision can be restored following a reasonably simple operation. Visual loss due to glaucoma can be minimised by early detection and treatment, but once vision has been lost it cannot be recovered. Much research is being done on the treatment of age-related macular degeneration, but this currently remains the main cause of irreversible loss of vision in the elderly. Results of macular hole surgery are improving due to improved surgical techniques and better diagnostic equipment (Optical Coherence Tomography). Underlying vascular disease (systemic hypertension, diabetes, atherosclerosis, vasculitis) is usually present in patients with retinal artery occlusion, retinal vein occlusion or anterior ischaemic optic neuropathy.