Seeing double – Sudden double vision

Sudden double vision is a symptom that always needs to be carefully examined, as quickly as possible.

Some of the questions that will get asked to help get to the cause of suddenly seeing double:

• Has there also been a change in vision at the same time? (Some things that affect eye movement can also affect the function of the optic nerve).
• Is there any eye discomfort? (If restrictions to eye movement are through the eye muscles getting swollen or entrapped, discomfort and diplopia can occur together.)
• Is the double vision side-by-side, or one-above-the-other, or some other relation? (This helps identify which eye muscles or type of eye movements are being affected)
• Does the degree of double vision change on your position of gaze, eg more as you look up, or down, left, or right? (This helps identify which eye muscles might be affected)
• Is it still there when you close one eye or the other?  (It may sound silly, but it’s possible to get double vision, or something that looks like double vision, in just one eye).
• Have you noticed any unequal pupil size? Is either eyelid droopy? (The nerve pathway for eye muscles is quite close to the pathway for the pupils; sometimes they will be affected together)
• Any other symptoms? headache?
• Any history of eye or head injury? medical conditions?

There are a quite a number of possible causes, and some of them need immediate attention – so don’t delay.