Why do I feel a slight pain in my eyes when I see a sharp object?

I experienced this since I was about 12 years old. I am now 20. I have asked even doctors about this, none have known what I am talking about. Every time I see something sharp pointed at my eyes, I cant help but squint or shut them. The pain is a pressure like someone poking me in the eyes, but from the inside of my skull. No matter how far away, as long as I can see it, I have to turn away. Common objects include pencils, cacti, table corners, etc.