What is a defining characteristic of cataracts?

A defining characteristic of cataracts is the opacity of the crystalline lens. Cataracts occur when the lens of the eye, which is normally clear, becomes cloudy or opaque, leading to blurred vision. This cloudiness can develop gradually over time, impacting the way light is transmitted to the retina, ultimately resulting in vision impairment. The condition can be associated with aging, but it may also be influenced by factors such as genetics, prolonged exposure to UV light, certain health conditions, and the use of specific medications.

The other options relate to different eye conditions. The separation of the retina refers to retinal detachment, which is a separate medical issue involving the retina pulling away from its normal position in the eye. Increased pressure in the eye is indicative of glaucoma, another distinct eye condition characterized by damage to the optic nerve, often related to increased intraocular pressure. Lastly, clouding of the cornea describes a condition that can occur due to various factors such as infections, injuries, or other diseases, but it is not the defining characteristic of cataracts. Understanding these distinctions helps clarify the nature of cataracts as specifically related to the crystalline lens's opacity.