Not having enough visual information, such as when you are in darkness, open spaces or travelling in a lift, can affect balance. Your eyes get their information about which way up you are from the environment.
This information is taken from vertical structures, such as buildings, trees and lamp-posts. These vertical structures need to be quite close to you to be useful for your balance system. Several types of environments do not provide enough visual information for your brain and so can result in dizziness and unsteadiness.
The most obvious of these is at night when it is dark, or when you are somewhere that only has dim lighting. There is also not enough visual information nearby when you are in large flat and open spaces (e.g. a field or park), or looking down from heights.