@maryb1996 In your description about the cube illusion, and your eyes shifting, I had another thought. Usually we have a dominant eye that does most of our focusing for close work. The brain puts the images together from both eyes for depth perception. What you might be describing is the dominance shifting between your eyes as you look at something. You can cover each eye by itself to figure out which eye is doing the seeing. My eyes don't converge well at close distances, and if I check this, the image from each of my eyes are a distance apart. Sometimes my brain just picks one, and that image can shift back and forth spontaneously, but when I concentrate, my brain ignores one of the images, but I am seeing and comprehending the image correctly. I've always been like this. You could be like this too. You might be having trouble combining images from your eyes. Have you seen an ophthalmologist? It might be a good idea in case there is something in the eye causing the wrong signals to be sent. An ophthalmologist is a medical doctor and an optometrist is not a medical doctor. The ophthalmologist can also write orders for imaging of the brain, and you may get a quicker appointment. The retina has rods and cones that convert the focused image into nerve impulses that are sent through the optic nerves to the brain where the information is processed in the visual cortex. Anything abnormal along that entire pathway can affect vision and processing. The optic nerves are on the underside of the brain and cross over in an "X" to the opposite side of the brain. If there was a mass or tumor putting pressure on the optic nerves, it could also affect the signals that are sent. These would be things that an MRI could show. I'm just thinking outside the box about how this works, so you can ask questions of your providers. I used to work for a neuroanatomist at a university who was mapping the visual system (and studying visual abnormalities) from the retina to the visual cortex.