How does retinitis pigmentosa primarily affect vision?

Retinitis pigmentosa primarily affects vision by causing a gradual loss of vision. This degenerative retinal disease typically starts with difficulty seeing at night (night blindness) and progresses over time to a loss of peripheral vision. As the condition advances, central vision may also be affected, ultimately leading to significant visual impairment or even blindness in severe cases. The gradual nature of this vision loss is a hallmark of the disease, distinguishing it from conditions that cause sudden vision loss.

The other options can be ruled out based on the characteristics of retinitis pigmentosa. For instance, the condition does not result in a sudden vision loss; instead, it has a slow and progressive course. Additionally, it does not enhance night vision, which is contrary to the symptoms experienced, as night vision typically deteriorates. Retinitis pigmentosa may also diminish color perception, rather than increase it, especially as rod cells (which are crucial for vision under low light) and, over time, cone cells (responsible for color vision) are affected.