How do cataracts develop?

Aging: Cataracts are a natural process of the lens fibers/proteins continuing to be produced but not removed, eventually leading to disorganization and thus disruption of light rays. This process can be accelerated by factors such as uv light and trauma or steroids. Everyone eventually gets cataracts -- it just depends on whether they are visually significant to the patient based on their visual needs.

Protein changes: Most common develops from natural protein changes in the lens of the eye, typically from aging and presumably long term uv exposure. It causes the lens to turn cloudy. Other causes are diabetes, steroids, and eye trauma.

Opacity of lens: The clear lens in the eye become opacified due to many reasons, trauma, medications, sun damage ....