Comment by rux

It is possible to have two fully working eyes but for your brain to lack the wiring to combine the two images into a single three dimensional construct in your brain. Your eyes can be fine yet you can have no binocular depth perception. If this is the case you'll not be able to see any Magic Eye pictures or SIRDSs, or get the benefit from going to a 3D showing of a film instead of a 2D showing.