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Unilateral diplopia is double vision that is noticed in one eye and can persist when the other eye is covered. It is often caused by an optical problem in that eye, such as a tear film issue, refractive error, or a lens or cornea change. This differs from binocular diplopia, which usually comes from eye misalignment and goes away when either eye is covered. New or sudden diplopia should be evaluated to rule out urgent causes.
read more about unilateral diplopia ...Most unilateral diplopia is related to how light is focused or scattered before it reaches the retina. Common causes include:
Less commonly, certain retinal conditions can create ghosting or image doubling.
Seek urgent care if diplopia starts suddenly or is paired with other concerning symptoms. Red flags include a severe headache, new neurologic symptoms, eyelid droop, or limited eye movements. A painful red eye with halos and nausea can suggest acute angle-closure glaucoma. Diplopia after head or eye trauma should also be evaluated promptly.
Clinicians first determine whether the double vision is monocular or binocular using a cover test. A pinhole test may be used because many refractive causes improve when looking through a small aperture. The exam usually includes refraction, slit-lamp evaluation of the cornea and lens, and measurement of intraocular pressure. If findings suggest a neurologic or orbital cause, imaging and specialist referral may be needed.
Treatment targets the underlying cause. Lubricating drops and lid care can help when dry eye is contributing, while updated glasses or toric contact lenses can correct refractive error. Cataract or significant corneal disease may require procedural or surgical care. If the problem is actually binocular diplopia, treatment may include prisms, vision therapy, or management of the underlying neurologic or muscular cause.
Unilateral diplopia is typically noticed in one eye and can persist when the other eye is covered. Binocular diplopia usually comes from eye misalignment and resolves when either eye is covered. The distinction helps guide the workup.
A pinhole reduces stray light and narrows the beam entering the eye. If the double image improves with pinhole, a refractive or optical cause is more likely. It does not rule out every cause, but it is a helpful screening step.
Yes. An uneven tear film can create irregular refraction and ghosting that feels like double vision. Symptoms often fluctuate and may improve temporarily after blinking or using lubricating drops.
Go urgently if diplopia is sudden or comes with severe headache, weakness, numbness, trouble speaking, eyelid droop, or restricted eye movement. Also seek urgent care for a painful red eye with blurred vision or halos. These signs can indicate time-sensitive eye or neurologic disease.
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