Blurry vision, particularly when it affects only one eye, can be disorienting. This means the affected eye is not focusing light correctly, leading to a loss of sharpness and clarity. While often temporary, it can also indicate a more serious underlying condition. Understanding why one eye’s vision might become blurry helps individuals recognize when to seek professional evaluation.
Temporary Causes
Temporary blurriness in one eye often stems from common, less severe issues that often resolve on their own. Dry eye syndrome occurs when eyes do not produce enough tears or tears evaporate too quickly, leading to discomfort and blurred vision. This can happen if the tear film is disrupted. Prolonged visual tasks, like extensive screen use or reading, can lead to eye strain and temporary blurriness.
Minor allergies can induce temporary blurriness, especially if one eye is exposed to allergens like pollen or dust, leading to irritation, tearing, or swelling. Allergic inflammation can disrupt the tear film, contributing to hazy vision. A foreign particle, such as dust or an eyelash, on the eye’s surface can cause irritation, tearing, and immediate blurry vision. Rubbing an eye can temporarily distort the cornea’s shape, leading to momentary blurring.
Underlying Eye Conditions
More persistent or progressive blurriness in one eye points to specific conditions affecting the eye’s structure or function. Refractive errors, such as nearsightedness (myopia), farsightedness (hyperopia), or astigmatism, occur when the eye’s shape prevents light from focusing precisely on the retina, causing blurred vision. These conditions can affect one eye more significantly than the other, leading to unilateral blur. Cataracts involve the clouding of the eye’s natural lens, which gradually leads to blurry or dim vision, often progressing in one eye initially.
Glaucoma, particularly acute angle-closure glaucoma, can cause a sudden increase in eye pressure, damaging the optic nerve and resulting in rapid blurry vision, typically in one eye. Macular degeneration affects the central part of the retina responsible for sharp vision, and its wet form can cause rapid central blurry vision in one eye due to abnormal blood vessel growth. A retinal detachment, where the light-sensitive tissue at the back of the eye pulls away, is a medical emergency that often causes sudden blurry vision, flashes of light, or a shadow in the visual field of one eye. Optic neuritis, an inflammation of the optic nerve, can lead to sudden blurry vision and pain with eye movement, often affecting one eye, and is sometimes associated with autoimmune conditions. Corneal abrasions or infections, injuries or inflammatory responses to the clear front surface of the eye, can cause pain, redness, and blurry vision in the affected eye.
Systemic Health Issues
Certain health conditions that impact the entire body can also manifest as blurry vision in one eye. Migraines, particularly retinal migraines, can cause short-lived episodes of blurry vision or even temporary blindness in one eye, often preceding or accompanying a headache. A transient ischemic attack (TIA) or stroke, which disrupts blood flow to the brain, can affect visual processing areas, resulting in sudden blurry vision or vision loss in one or both eyes, often alongside other neurological symptoms like weakness or confusion.
Diabetes can lead to diabetic retinopathy, a condition where high blood sugar levels damage tiny blood vessels in the retina, potentially causing blurry vision if bleeding or swelling occurs, affecting one eye more than the other. Multiple sclerosis (MS) is a neurological disorder that can cause optic neuritis, leading to sudden blurry vision and discomfort in one eye as the immune system attacks nerve fibers. Giant cell arteritis is an inflammatory condition affecting blood vessels, which can reduce blood flow to the optic nerve and cause sudden vision loss in one eye, if not promptly treated.
When to Seek Medical Care
Seek medical care for blurry vision in one eye, especially when certain symptoms accompany it. Immediate medical attention is necessary for sudden blurriness, particularly if associated with eye pain, sudden vision loss, or double vision. Other urgent indicators include severe headaches, sudden weakness or numbness on one side of the body, changes in pupil size, or seeing flashes of light or new floaters. These symptoms could signal serious conditions like retinal detachment, acute angle-closure glaucoma, stroke, or optic neuritis.
For less urgent but concerning symptoms, schedule an appointment with an eye care professional. This includes blurry vision that develops gradually, is mild and intermittent, or occurs without other alarming symptoms. If the blurriness is persistent but not severe, or if there is a known history of a benign eye condition that might be flaring up, a routine eye examination can help determine the cause and appropriate management, and is important for monitoring eye health and detecting potential issues early.