A concussion cataract may occur in blunt trauma. The lens capsule is not grossly damaged but becomes progressively opaque over a period of months. The lens should be removed.
A penetrating injury to the eye may perforate the lens capsule. Usually, an opacity develops over the entire lens. Frequently, there is accompanying inflammation as lens material extrudes into the anterior chamber. In younger patients, the entire lens may be autolysed.
The effects of foreign bodies within the lens are varied. Glass and plastics are well tolerated but siderosis from iron and chalcosis from copper cause characteristic opacities.
Chemical injury, particularly involving alkalis, and radiation injury, are also sources of cataract. Over exposure to heat results in the "glassblower's cataract."