Blurry vision in one eye is a common concern, indicating a change in how the eye processes visual information. Objects may appear out of focus or hazy. This symptom is not a diagnosis but a signal that something is affecting the visual system. Any noticeable change in vision, especially if sudden or worsening, warrants professional evaluation.
Eye-Specific Reasons
Blurry vision in one eye often originates from conditions directly affecting the eye’s structure or function. Refractive errors, such as myopia (nearsightedness), hyperopia (farsightedness), and astigmatism, are among the most common causes. These conditions occur when the eye’s shape prevents light from focusing correctly on the retina, leading to blurred or distorted vision at various distances.
Dry eye syndrome can also lead to fluctuating blurry vision. This occurs when the eyes do not produce enough tears or when tear quality is poor, disrupting the tear film. This can make the eye surface irregular, causing light to scatter and vision to blur.
Cataracts, which involve the clouding of the eye’s natural lens, are another frequent cause, particularly as people age. This clouding scatters light, preventing a sharp image from reaching the retina and resulting in gradually worsening blurry or dim vision.
Glaucoma, a group of conditions damaging the optic nerve, can also cause blurry vision, often with a gradual loss of peripheral vision, though some types can cause sudden blur.
Macular degeneration, especially the wet form, affects central vision, leading to blur or distortion as it impacts the macula. Retinal issues, such as retinal detachment or diabetic retinopathy, are serious conditions that can cause sudden or progressive blur. Retinal detachment occurs when the retina pulls away from its supporting tissue, leading to shadows or a “curtain” over vision. Diabetic retinopathy involves damage to retinal blood vessels due to high blood sugar.
Inflammation of the optic nerve, known as optic neuritis, typically causes pain with eye movement and temporary vision loss or blur in one eye. Temporary blur can also result from eye strain, often due to prolonged visual tasks like looking at digital screens, which reduces blinking and affects the tear film.
Body-Wide Health Connections
Beyond eye conditions, blurry vision in one eye can also stem from systemic health issues. Diabetes is a significant example, where uncontrolled blood glucose levels can damage tiny blood vessels in the retina, leading to diabetic retinopathy and macular edema, both causing blurry vision. High blood pressure can similarly affect retinal blood vessels over time, leading to vision changes.
Migraines are another connection, with some individuals experiencing a visual aura, including temporary blur, blind spots, or flashing lights, that can precede or accompany a migraine attack. A stroke or transient ischemic attack (TIA) can impact the brain’s visual processing centers, resulting in sudden blurry vision or vision loss in one or both eyes.
Certain autoimmune diseases, such as multiple sclerosis (MS), have a strong association with optic neuritis, causing inflammation of the optic nerve that leads to blurry vision and pain in one eye. Various medications can also have side effects that include visual disturbances, leading to temporary or persistent blur.
When to Seek Immediate Care
Certain symptoms accompanying blurry vision in one eye signal a medical emergency, requiring immediate professional attention to prevent permanent vision loss or address a serious health crisis. A sudden onset of significant blurry vision is a primary indicator for urgent evaluation, especially if marked or affecting only one eye.
The presence of associated pain, whether severe eye pain or a sudden, intense headache, should prompt immediate medical consultation. Any degree of vision loss, partial or complete, alongside the blur, necessitates emergency care.
Other concerning visual changes include a sudden increase in flashes of light or new floaters, which are small dark spots or squiggly lines drifting across vision. A dark curtain or shadow moving across or covering part of the visual field is another symptom.
Double vision, especially if sudden, also warrants immediate medical assessment. If blurry vision follows a recent eye injury or trauma, or is accompanied by redness or discharge from the eye, prompt attention is necessary. Systemic symptoms like numbness, weakness on one side of the body, or difficulty speaking, combined with blurry vision, could indicate a stroke and require emergency medical services.
What to Expect at the Doctor
When experiencing blurry vision in one eye, an eye care professional, such as an optometrist or ophthalmologist, will conduct a thorough examination to determine the cause. The process typically begins with a comprehensive eye exam, including tests for visual acuity to measure sharpness of vision. A slit lamp exam allows for detailed viewing of the eye’s front structures, while a dilated eye exam enables the doctor to inspect the retina and optic nerve at the back of the eye. Eye pressure measurement is also routinely performed.
Depending on the initial findings, additional specialized tests may be necessary. A visual field test can detect blind spots or areas of vision loss, common in conditions like glaucoma. Optical coherence tomography (OCT) provides high-resolution cross-sectional images of the retina, helping to identify subtle changes or swelling. Fundus photography captures detailed images of the back of the eye, aiding in monitoring conditions like diabetic retinopathy or macular degeneration over time.
The doctor will also take a detailed medical history, asking about the onset and nature of symptoms, general health conditions, current medications, and family eye history.
Once a diagnosis is made, management approaches vary widely based on the underlying cause. For refractive errors, corrective lenses like glasses or contact lenses are often prescribed. Medications, often eye drops, may be used for conditions like dry eye, glaucoma, or inflammation. Oral medications might also be prescribed for systemic conditions impacting eye health.
For more advanced issues such as cataracts or retinal detachment, surgical procedures may be recommended to restore vision. If a systemic health condition is suspected as the root cause, a referral to another medical specialist, like a neurologist or endocrinologist, may be made for co-management. Lifestyle adjustments, such as managing screen time for eye strain or controlling underlying health conditions, are also frequently advised.