Concept: This question tests your knowledge about the harmful effects of ultraviolet (UV) radiation on the human eye, specifically identifying which eye disorder is directly caused by prolonged exposure.

Why (A) is correct: Prolonged exposure to UV radiation, especially UV-B, is a significant risk factor for the development of cataracts. Cataracts involve the clouding of the eye's natural lens, leading to blurred vision. UV radiation causes oxidative damage to the proteins in the lens, leading to their aggregation and opacification.

Why other options are wrong:

• (B) Glaucoma: Glaucoma is primarily caused by increased intraocular pressure, damaging the optic nerve, and is not directly caused by UV radiation.
• (C) Dilation pupil: Pupil dilation (mydriasis) is a normal physiological response to low light or certain drugs, not a disorder caused by UV radiation.
• (D) Some defect of retina: While excessive UV exposure can contribute to retinal damage (like macular degeneration), cataracts are a more direct and commonly cited disorder caused by UV radiation among the given options.

NEET Tip: Remember that wearing UV-protective sunglasses is crucial to prevent eye damage from sun exposure.

Correct Answer: (A)