I don't know too much about this area, but I do know that this kind of task involves a bunch of complex processing in the brain. The more "Mechanical" aspects of vision could be described as visual acuity (sharpness of vision). However, gauging whether something is wonky would be a visual discrimination task, which involves more work by the brain. It's an area in which one's skill can be improved through learning, and some occupations have a lower discrimination threshold (I e. They can detect smaller differences).