Evolution of affordable assistive technologies like eye tracking help people with motor disabilities to access information on the Internet or work on computers. However, eye tracking environments need to be specially built for better usability and accessibility of the content and should not be on interface layouts that are conducive to conventional mouse or touch based interfaces. In this work, we argue the need of the domain specific heuristic checklist for eye controlled interfaces, which conforms to the usability, design principles and less demanding from cognitive load perspective. It focuses on the need to understand the product in use inside the gaze based environment and then apply the heuristic guidelines to design them. We propose an eight-point questionnaire to validate the usability heuristic guidelines for eye-controlled interfaces.