Blurry vision in one eye, also known as monocular blurry vision, describes a loss of sharpness or clarity in the sight of only one eye. This symptom can range from a slight haziness to a significant reduction in visual acuity, making it difficult to discern fine details or see objects clearly. While often benign, it can signal an underlying condition requiring attention.
Common Reasons for Blurry Vision in One Eye
Refractive errors, such as astigmatism, myopia (nearsightedness), hyperopia (farsightedness), or presbyopia (age-related farsightedness), might affect one eye more than the other or develop unevenly. For instance, astigmatism, involving an irregularly shaped cornea or lens, can cause blurry vision in a single eye if its severity differs between the two eyes. Dry eye syndrome, characterized by insufficient tear production or poor tear quality, can also cause fluctuating blurriness or a gritty sensation in one or both eyes.
Eye strain or fatigue, often from prolonged screen time or reading, can temporarily reduce visual clarity in one eye. Ocular migraines, visual disturbances that may occur with or without a headache, can also manifest as temporary blurriness, blind spots, or flashing lights in one eye. Temporary irritation from a foreign body, such as a speck of dust, or an allergic reaction can lead to acute blurriness alongside redness and discomfort.
Early-stage cataracts, involving the clouding of the eye’s natural lens, develop gradually and can initially affect one eye more prominently. This can cause progressive blurring of vision, often with increased glare sensitivity or faded colors. These common causes are manageable, sometimes with simple interventions like corrective lenses, eye drops, or resting the eyes.
Urgent Medical Conditions Causing Blurry Vision
More serious medical conditions can cause blurry vision in one eye and require immediate evaluation. Retinal detachment, where the light-sensitive tissue at the back of the eye pulls away from its supporting layers, can cause sudden blurry vision, often described as a shadow or curtain moving across the field of vision. This often occurs alongside flashes of light or an increase in floaters. Optic neuritis, an inflammation of the optic nerve, can lead to sudden blurry vision or vision loss in one eye, frequently accompanied by pain with eye movement.
Acute angle-closure glaucoma, a sudden increase in eye pressure, can cause rapid and severe blurry vision, intense eye pain, headache, and sometimes nausea or vomiting. This condition is a medical emergency that can lead to permanent vision loss if not treated promptly. Macular degeneration, particularly the wet form, can cause sudden blurry vision or distortion in the central vision of one eye due to abnormal blood vessel growth under the retina.
A stroke or transient ischemic attack (TIA), affecting blood flow to the brain’s vision centers, can manifest as sudden, painless vision loss or blurriness in one eye. Amaurosis fugax, a temporary loss of vision in one eye, is often likened to a “curtain coming down” and results from a temporary blockage of blood flow to the eye. Corneal abrasion or infection can cause sudden blurry vision, pain, redness, and sensitivity to light in the affected eye. Uveitis, an inflammation of the uvea, can also lead to blurry vision, pain, light sensitivity, and redness in one eye.
When to Seek Professional Medical Attention
Seek professional medical attention if you experience blurry vision in one eye, especially with certain “red flag” symptoms. Sudden onset of blurry vision, particularly without warning, warrants immediate medical evaluation. If accompanied by pain, redness, or discharge, it could indicate an infection, inflammation, or injury. Vision loss coupled with systemic symptoms like headache, dizziness, weakness, or difficulty speaking suggests a potential neurological event and requires emergency care.
Flashes of light, new or increased floaters, or a “curtain” or “shadow” obscuring part of your vision are signs of a potential retinal issue, necessitating urgent assessment. Any vision changes following a direct eye injury or head trauma also require prompt medical attention. If blurry vision persists, does not resolve, or progressively worsens, consult an eye care professional.
The Diagnostic Process and Management Options
An eye care professional will begin with a comprehensive eye examination. This includes a visual acuity test to measure vision sharpness, a refraction test for corrective lenses, and a slit-lamp examination to view the eye’s front and internal structures. A dilated eye exam, using eye drops to widen pupils, allows the doctor to inspect the retina and optic nerve. Depending on initial findings, further diagnostic imaging tests, such as optical coherence tomography (OCT) or fluorescein angiography, might be performed to visualize specific layers of the retina or blood vessels.
Management options depend on the identified underlying cause. For refractive errors, corrective lenses like glasses or contact lenses are prescribed to restore clear vision. Dry eye syndrome can be managed with lubricating eye drops, lifestyle adjustments, or prescription medications that stimulate tear production. Bacterial or viral eye infections may require antibiotic or antiviral eye drops.
More complex conditions require specialized treatments. Retinal detachments often require surgical repair to reattach the retina, while cataracts are removed through surgery and replaced with an artificial lens. Inflammatory conditions like optic neuritis or uveitis may be treated with anti-inflammatory medications, such as corticosteroids. For systemic conditions affecting vision, such as stroke or certain autoimmune diseases, referral to other medical specialists for comprehensive management is often necessary.