Visual testing systems encompass a broad category based on their specific application. They include special cataract quantifiers, anomaloiscopes for color-blindness tests, and other multi-role ophthalmology testing systems. Although they differ in resolution, computer interface capabilities and intended application, they all interface with the patient through a binocular viewing port. A cataract quantifier is will detect the amount of stray-light scattered, thus detecting cataracts that may not be found by other tests. Visual testers come with multiple settings for applications such as general medical practice, optometry, pediatric and school health, or driver licensing. Look for machines that can simulate environmental conditions such as day and night, and indication of when environmental controls exceed the accepted standards.