Since starting with helis I've had a problem with depth perception, especially at distance, that has been holding my flight progress back. Went to the eye doctor yesterday since I was having difficulty reading with my left eye. The short of it is I've got cataracts. He said its with both eyes with the left being the worse, was suprised I wasn't complainting about them both. I go to have the left corrected in two weeks, the right at a later date. Hope this helps since I've somewhat stagnated on my learning curve.