I didn't wear glasses until I was a day away from turning twenty-eight. I had occasionally been given reading glasses that never really helped, but just before graduating from seminary, I got "real" glasses full-time. Why? Because you really can read so much your eyes can no longer naturally focus on things farther away than a book. My theological education had left me woefully nearsighted.
Ironically, being nearsighted where the faith is concerned is something rather strongly condemned in 2 Peter 1:5-9:
For this very reason, make every good effort to add to your faith goodness; and to goodness, knowledge; and to knowledge, self-control; and to self-control, perseverance; and to perseverance, godliness; and to godliness, mutual affection; and to mutual affection, love. For if you possess these qualities in increasing measure, they will keep you from being ineffective and unproductive in your knowledge of our Lord Jesus Christ. But whoever does not have them is nearsighted and blind, forgetting that they have been cleansed from their past sins.
Here, then, Peter isn't talking about being literally nearsighted (thankfully for me!). He's speaking about a sort of spiritual nearsightedness that means people can't see the road behind him.
Over the last several weeks, we've heard testimonies from people sharing their stories of God's faithfulness to them in the past. These people have not been nearsighted or blind; their memories are long enough to remember where God brought them from. We should all keep that in mind -- not to brag about how bad we were, but to humbly praise God for how great He is.
Maybe we need some spiritual glasses to fix our spiritual nearsightedness. Whenever we're tempted to pride, being judgmental, or something else, we could put on our glasses and see the people we used to be. We could remember we "have been cleansed from [our] past sins" and bought with a great price. We could remember the goodness and mercy of an awesome God.