Change sunglasses when tappes

This should work for you - will work with as many glasses needed:

//@input SceneObject[] glasses

var currentPair = 0;

for(var i = 0; i<script.glasses.length; i++)
    script.glasses[i].enabled = false;

script.glasses[currentPair].enabled = true;

script.createEvent("TapEvent").bind(function(){
    script.glasses[currentPair].enabled = false;

    currentPair = getNext();
    script.glasses[currentPair].enabled = true; 
});

function getNext(){
    if(currentPair + 1 >= script.glasses.length)
        return 0;
    else
        return currentPair + 1;

}

put this into a script component.