Thank you very much for helping out.
I need your assistance in one more thing: I have gaze points but I need to find the angle. For example:- The distance between observer and screen is 30cm. In the screen an object moves in an elliptical motion. So how do i calculate the visual angle made in every 0.5 seconds ? Can the tangent formula be used ? Because in the elliptical motion the object moves at so many random angles, so how to assume perpendicular and base value to calculate the tangent ?
Just this query. Thank you for your assistance.