We dilate because it is the only way to see all parts of the back of your eye. There is no substitute. Repeat, there is no substitute. You don't have to be dilated every exam, it varies by age and particular circumstance, but at least every four years, for everyone. And it's free! So, when we ask if we can dilate your eyes, remember that it's the best and most complete health check, and that's why we go to this extra effort. Thanks!