This horse isn’t blindfolded, and can see and hear perfectly well. He’s been fitted with a flymask by his owner to stop the irritation from flies, bugs and mosquitoes that drive grazing horses mad and spread disease and infection. They’re not a universal thing but their use seem to be more and more prevalent. The mask is acoustically and visually nearly transparent to the equine who can potter about the paddock untroubled by insects.
I hope that clears it up for the people who messaged me with some concern for dobbin’s welfare.