double vision 
noun [mass noun]
The simultaneous perception of two images, usually overlapping, of a single scene or object.Because using both eyes in the presence of squint/refractive error would cause significant eye-strain and double vision, the brain ignores the image from the squinting eye, resulting in amblyopia....
- She reported that when she first saw him he had occasional double vision, mild photophobia and tenderness below the left eye.
- Common symptoms are pain, an oppressive feeling behind the eye, a gritty sensation in the eye, double vision, and photophobia.
- beat the clock
- beat the count
- beat the drum for
- be at the end of
- beat the pants off
- be at the races (or in the race)
- beat the rap
- beat the system
- be at the top of one's game
- Beattie, Ann
- beat time
- Beatty, David
- Beatty, Warren
- beat-up
- beat up on someone
- beau
- Beaubourg Centre
- beaucoup
- beaucoup de
- Beaufort scale
- Beaufort Sea
- beau geste
- beau idéal
- Beaujolais
- Beaujolais Nouveau