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Refractive diplopia is double vision caused by an optical focusing problem in the eye, rather than an eye alignment problem. It is often monocular, meaning the doubling stays when the other eye is covered. Uncorrected astigmatism, an uneven tear film, or corneal surface irregularity can split light and create a second image. The problem often improves with the right prescription or surface treatment.
read more about refractive diplopia ...Uncorrected astigmatism is a common cause because light focuses at more than one point and creates ghosting. Dry eye and tear film instability can also create optical distortion that looks like doubling. Corneal problems such as keratoconus, corneal scars, or an irregular corneal surface after surgery can lead to refractive-style double images. Early cataract changes can cause light scatter and split images, even before vision looks very cloudy. An eye exam checks each of these possibilities because treatment depends on the driver.
Symptoms usually include ghosting or two images in one eye, especially around high-contrast edges like text on a bright screen. Glare and halos around lights can become more noticeable at night. The doubling can vary during the day, which often points to dryness or contact lens fit issues. Closing one eye can reduce confusion, but the doubling can remain in the affected eye if it is monocular diplopia. Sudden new double vision with pain, weakness, or drooping eyelid needs urgent evaluation because that pattern can signal a different cause.
A clinician first separates monocular diplopia from binocular diplopia by asking what happens when one eye is covered. A pinhole test is often used because refractive-type doubling often improves when light is narrowed through the pinhole. Refraction testing checks whether an updated glasses or contact lens prescription removes the second image. A slit-lamp exam evaluates the tear film, cornea, and lens for dry eye, irregular surfaces, or early cataract changes. Corneal topography can be added when keratoconus or other shape irregularity is suspected.
Treatment often starts with correcting the refractive error using updated glasses or contact lenses, especially when astigmatism is the main driver. Dry eye care such as lubricating drops, lid hygiene, and environmental changes can reduce ghosting when tear film instability is involved. When corneal shape irregularity is present, specialty contact lenses or corneal treatment plans can reduce doubling by creating a smoother optical surface. If a cataract is driving the symptoms, cataract surgery can resolve the optical splitting once the cataract becomes visually significant. New persistent double vision should be assessed before driving at night or changing contact lens wear habits.
It is usually monocular. The doubling often stays when the other eye is covered because the issue is in the optics of the affected eye. Binocular diplopia usually points to eye misalignment and goes away when either eye is covered.
Often, yes. Improvement with pinhole suggests a refractive or optical cause. An eye exam still checks the cornea and lens to find the exact driver.
Glasses can fix refractive diplopia when the cause is uncorrected astigmatism or an inaccurate prescription. Contact lenses can also help, especially for irregular corneas when specialty lenses are used. Dry eye treatment may still be needed if symptoms vary across the day.
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