I will have to second the idea of being hydrated and well rested for your eye exam. I had 20/20 my entire military career and when I took my eye exam at OCS they said I had 20/30. I am getting ready to start API now and recently had a re-evaluation for my eyes. I got a good 8 hrs of sleep and hydrated the best I could and now I got back to 20/20 and no longer am required to wear glasses. The optometrist said sleep, hydration, diet, and stress have a huge impact on your vision. My recommendation is that if you have some of these factors not working in your favor, try to get another appointment when you can get them to work in your favor.