Why are objects viewed in monovision 2" apart horizontally?

[OhMyEye]

I currently have severe macula pucker due to residual ERM, and about a mid stage cataract same eye (right).  Recently saw a retinal surgeon who recommended cataract surgery then ILM peel.

In the past few days I discovered that images of the same object, when viewed through each eye (with other eye closed) always appears 2" apart.

For example, I'll look at a table lamp with my right eye only, then my left eye only, and the lamp is 2" to the left of where I saw it with my right eye.

Conversely, I'll look at the same lamp with my left eye only, then my right eye only, and the lamp is 2" to the right of where I saw it with my left eye.

I never noticed this before.  Is this normal?

Or is it caused by my cataract and/or macula pucker?

Could this 2" difference in image location be what gives me severe eye aches at times?

[JohnHaganMD]

It's normal. It's because your two eyes are proably about 2 inches apart. The apparent movement of an stationary object when viewed from two different perspectives is called parallax.  The different views is the basis for 3D vision (depth perception)