Noticable delay in checkmark showing/hiding when clicking on checkbox on mobile

I am using the ngTouch module in Angular 1.3.12, running on both iPad and desktop. I have a checkbox input wrapped in a label so that both checkbox and label will detect a touch:

<label><input ng-click="doCheck()" type="checkbox" name="checkbox" id="checkbox1" ng-model="myModel"/>My label</label>

Using ngTouch's ng-click directive does appear much more responsive on the iPad, however in this case, I notice that even though I am able to touch quickly on the checkbox or label, the checkmark only toggles after a slight delay.

How can I make this respond faster?