Cataract: window for systemic disorders

Cataract is the leading cause of visual handicap throughout the world, and almost all elderly individuals develop lens opacities. Epidemiological studies have shown that nuclear cataracts in young adults are associated with higher mortality. Many cataractogenic stressors induce endoplasmic reticulum (ER) stress, which in turn induces the unfolded protein response (UPR). The UPR can damage or kill a wide range of cell types and may be involved in many human diseases. We hypothesize that a cataract can be considered a window that can indicate the presence of systemic disorders. This is important because cataract is easily detected during a routine ocular examination. The slightest opacity in any region of the lenses, especially in younger patients, may be a sign of systemic disorders. Earlier detection of systemic disorders can save the lives of patients. If our hypothesis is correct, then elimination of known ER/cataractogenic stressors from individuals with cataracts should be the one of the first steps for treatments of the systemic disorders. We discuss the potential risk factors and beneficial effects of removal of such risk factors in patients with early cataracts. All patients with cataract should be referred for comprehensive medical examination.