Stupid Question

[EpBurns]

This has been a wonderment for me for some time and it is horse racing related but not about the actual horses that are running ,I have never seen this anywhere but California but it is bothering me the Outriders on track in Cali sometime have there horses eyes covered with something that looks like a full blinker set but no eyes for the horse to see, I know a horse doesnt need to see to be ridden but for what reason would they shield the horses eyes and not allow them to see. Just wondering?