What is diplopia?

What is diplopia?

Diplopia is the medical term for double vision or seeing double. Diplopia is defined as seeing two images of a single object when you’re looking at it.

Double vision is usually a temporary issue, but it can also be a sign of more serious health conditions. Even if it’s caused by something as simple as needing new glasses, it’s important to get your eyes examined by your healthcare provider right away if you start seeing double.

Monocular vs. binocular diplopia

Your healthcare provider will classify your double vision as either monocular (one eye) or binocular (both eyes). Monocular diplopia is present when you use only one eye at a time. It may appear as a shadow. Binocular diplopia is present when both eyes are open at the same time. It goes away if you cover one of your eyes.

Monocular diplopia is more common and usually less serious. Binocular diplopia is usually caused by your eyes being out of alignment or other, more serious underlying conditions.

Horizontal diplopia vs. vertical diplopia

If you have binocular diplopia, your double vision can appear either vertically (top to bottom) or horizontally (side to side). Which one you have depends on what’s causing your diplopia and how (or why) your eyes are out of alignment.