Chronic eye fatigue. Please help.

I have been suffering from a wird eye problem since last 6 years. It started with my eyes becoming heavy and tired whenever I stepped out in daylight. Gradually, it became so frequent that I could hardly concentrate on even household chores without heavily stressing my eyes. Even a good night sleep couldn't help much now. I visited few doctors and they all found nothing wrong with my eyes (eyesight remained unchanged, Left Cyl -1, Right Cyl -1.75). Initially applying dry eye lubricant  and doing pen-point exercise helped, but it has become so severe now that whenever I visited a place where rapid eye movement is needed, like mall shopping, crowded spots etc. it became extremely difficult to even keep my eyes open: foggy, light headed and forgetting what to do. Even coordination between hearing and seeing gets impaired. Please help.