This verse speaks of heaven. Imagine how bright heaven will be and the only light will be from the Lamb, Jesus Christ Himself. I think of this passage sometimes on sunny days. I am convinced that the Lord gives us plenty of symbols in our day to day lives to try and understand heavenly concepts.
Daytime is like heaven. The sun is so bright you can't even look at it without damaging your eyes. So, if daytime is like heaven, then what is nighttime like? Well, when we see the moon, it's not actually light from the moon, rather it is reflecting the sun's light. I imagine nighttime to be earth, which is dark with sin. The moon is Christ's presence on earth. Sometimes it's more visible than others (full moon verses crescent moon). An amazing thing for me to ponder is the stars. Jesus Christ, speaking to His disciples, said, "you are the light of the world." Imagine how dark the night sky would be without stars?
Well, I think the Bible gives us a glimpse of what it will be like. One day Christ Jesus will come back to the earth and bring all believers with Him back to heaven, more commonly referred to as the rapture. Many, many Christians look forward to that day. So, according to my thought process, it will be like nighttime without the moon or stars. Listen to these verses in Amos: " 'Behold, the days come,' says the Lord God, 'that I will send a famine on the land, not a famine of bread, nor a thirst for water, but of hearing the words of the Lord. They shall wander from sea to sea and from north to east; they shall run to and fro, seeking the Word of the Lord, but shall not find it.' " Chapter 8 verse 11, 12