Snapshot A 72-year-old man is referred to an ophthalmologist for slowly progressive vision loss in both eyes. He reports difficulty driving at night due to glare from headlights. His medical history is unremarkable. The patient undergoes pupil dilation and a comprehensive slit-lamp examination. He is found to have significant opacification of the lens in both eyes. Preparations are made to schedule him for cataract surgery. SUMMARY A cataract is an opacification of the intraocular lens presents with a decrease in vision most common cause of reversible blindness Diagnosis is made clinically with a comprehensive eye examination Treatment is with cataract surgery, which involves removing the natural opacified lens and replacing it with a clear artificial intraocular lens Epidemiology Incidence affect over 24 million people over the age of 40 in the United States Risk factors increasing age non-age-related risk factors diabetes mellitus corticosteroid use UV exposure cigarette smoking ocular trauma prior ocular surgery genetic predisposition radiation or chemotherapy ETIOLOGY Pathophysiology age-related cataracts degenerative changes in the cellular structure of the lens which causes the lens to harden and lose its transparency Presentation Symptoms blurred vision glare and halos around lights difficulty with night vision Physical exam opacification of the lens darkening of the red reflex Differential Refractive error key differentiating factors no significant lens opacification as seen in cataracts Glaucoma key differentiating factors signs of optic nerve damage on examination in glaucoma intraocular pressure may be increased in glaucoma Diabetic retinopathy key differentiating factors signs of nonproliferative diabetic retinopathy, including retinal hemorrhages neovascularization in proliferative diabetic retinopathy DIAGNOSIS Clinical diagnosis Treatment Surgical cataract surgery indication visually-significant cataract technique removal of the opacified lens and insertion of a clear artificial intraocular lens Complications Reversible blindness Endophthalmitis following cataract surgery Prognosis High success rate of satisfactory visual outcomes with cataract surgery