Which part of the eye is primarily affected by cataracts?

The lens of the eye is primarily affected by cataracts. A cataract occurs when the proteins in the lens clump together, causing the lens to become cloudy and impairing vision. The lens is responsible for focusing light onto the retina, and when it becomes cloudy, it can lead to blurred vision, difficulty seeing at night, and faded colors. As cataracts progress, they can severely impact a person's ability to see clearly, often requiring surgical intervention to restore clarity through lens replacement. Understanding that cataracts directly impact the lens clarifies why this option is the correct answer.