Specialty Vision · Vision symptoms

Why do I see double?

Double vision (diplopia) is seeing two overlapping or side-by-side images of one object.

What it looks like

If covering one eye makes the doubling go away, the two eyes aren't aiming together — from a muscle imbalance (strabismus) or trouble converging up close. If the doubling stays with one eye covered, the cause is within that eye, such as astigmatism, a cataract or dry eye. Sudden double vision — especially with a headache, droopy eyelid or weakness — can signal a nerve or brain problem and is an emergency.

Possible causes — see what each looks like

When to see an eye doctor

Long-standing mild doubling can be assessed routinely. Seek urgent care for new, sudden double vision, or double vision with a severe headache, droopy eyelid, weakness or slurred speech.

Seek urgent care for:

Frequently asked questions

Is double vision an emergency?

Sudden double vision — especially with a headache, droopy lid, weakness or slurred speech — can signal a nerve or brain problem and needs emergency care. Long-standing mild strain is usually benign.

Can double vision be corrected?

Often, yes — with glasses or prisms, vision therapy, or eye-muscle surgery for misalignment, or by treating a single-eye cause such as astigmatism or a cataract.

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