Why do I have vertigo only on metal see-through stairs> and if there is any cure?

Fixate on top step. The remedy is to fixate your eyes on the top step or above and walk towards it. You need to avoid looking at the rapidly alternating horizontal stripe movement. It only happens when going up, since you are facing away from it coming down.
Vestibulovisual miss. In a closed staircase, your eyes perceives the vertical motion in sync with your inner ear's perception of motion. See thru stairs, the movement of the stripes of each slat vertically across your visual field gives an abnormal sense of movement because your eyes naturally fixate, track, jump to the next, fixate, track (effect: like train going by can make you feel like u r moving ).