I visited an eye doctor recently and had to take my contacts out of my eyes. I had to sit in a waiting room with a TV without my contacts the screen was a blur, the faces surrounding me were muted and reading from a distance was just not going to happen. Like all things in life when one of your senses is temporarily impaired you realize how important it was to have it in the first place.
When we walk away from our faith we seem to search for something to take its place; a new car, a cool trinket, a different hobby, a new friend. Although these things and people may give you joy and comfort they will never fulfill that void where your faith once was. Your sight like mine will change. Life will become more blurred when you lose your focus. God is not one of your senses but faith is needed to keep your life in balance… without your faith as your focal point in life all priorities shift and your life changes. What was important is not any longer. Faith gives you a clear path to what is important in life; family, friends, and how to be a better person. If accumulating things is your main focus in life then you have missed giving, volunteering and loving your fellow man. If giving, growing and loving others is your main priority then you are growing closer to God for God is love.
Your vision should be checked from time to time to make sure that sense is working efficiently. Your faith should be evaluated from time to time to make sure your faith and life are in focus. The sight of God is the most important sense you will ever need; the rest will fade away with age but God will remain.