What causes night blindness to happen?

Nyctalopia: Or night blindness is a symptom of something else such as myopia or malnutrition it is treated based on the cause. It is the inability to see at night or in low light environment.

Inherited Disease: Retinitis pigmentosa is a group of inherited disorders that cause degeneration of the retina and vision loss. The condition can be inherited in multiple ways and has a variety of symptoms. The most common ones are night blindness and gradual loss of peripheral vision. There is currently no proven treatment, however gene therapy is being explored as a possibility.