Binocular single vision
Binocular single vision is the ability of both eyes to focus on the same object simultaneously and perceive it as a single image.
Grades of binocular single vision:
Grade 1. Simultaneous perception
Both eyes perceive images at the same time.
Grade 2. Fusion
The brain combines two slightly different images into one single image.
Grade 3. Stereopsis
The highest level — gives perception of depth and 3D vision.
