What condition is characterized by cloudy lens leading to impaired vision?

Cataracts are a condition characterized by the clouding of the lens in the eye, which can lead to significant impairment of vision. The lens is responsible for focusing light onto the retina. When it becomes cloudy due to the formation of cataracts, the quality of the image perceived by the retina is compromised. This can manifest as blurry vision, difficulty with night vision, and halos around lights, among other symptoms. Over time, cataracts can progress, resulting in more severe visual impairment if left untreated.

In contrast, other conditions like glaucoma involve increased pressure in the eye that can lead to optic nerve damage, macular degeneration affects the central part of the retina leading to loss of central vision, and diabetic retinopathy is the result of damage to the blood vessels in the retina due to diabetes. None of these conditions primarily involve the clouding of the lens itself, which distinguishes cataracts as the correct answer.