Night blindness is caused by lack of Vitamin A. So you can take in a lot of vitamin A which is rich in foods and supplements. You can eat orange coloured fruits and vegetables, like carrots to treat night blindness.
If the night blindness is genetic, there is little chance that it can be cured. But if it is temporary and caused by deficiency of Vitamin A, you can take more food high in Vitamin A such as carrots to cure it.