The focussing ability of the eye changes in the dark. That is because the pupil dilates and this changes the eye’s aperture. In dim light, we experience “Night Myopia” and so we have trouble seeing far distances.
Second, poor nutrition, especially low levels of Vitamin A, can contribute to poor night vision.
Third, any kind of eye nerve problem, such as what can happen in Multiple Sclerosis (light desaturation) can lead to Night Myopia.
Fourth, an undiagnosed minor eye muscle coordination problem called a Latent Tropia can contribute to blurred or even disoriented vision at night. This eye deviation is too small to see in a mirror, but big enough to make things very blurry at night.