Night vision is your ability to see in poor lighting conditions. Your color vision isn't very good at detecting low light levels, as the light dims your visual cortex depends more and more on your black and white vision and ignores the color input. You have fewer black and white detectors than color detectors, so you have less visual acuity at the same refraction. You may need to wear Full correction instead of Normalized lenses in poor light.
Vitamin A might help nighttime vision.