During WW2 Britain made a series of Anti-Gas Eye Shields that became famous when they were used by German Field Marshall Erwin Rommel and his forces to block the sand and sun in their eyes during combat. I hope you can had this to the BATTLE OF TUNISIA campaign logistics tab possible under binoculars tab for soliders should be an easy place to place it.
The glasses would be great has the suns rays on sertion slopes make getting a good shot hard but this should increase the visibility for shots. I think this should be a Lv. 13 - 20 unlock.