What Causes Blurry Vision in One Eye?

Brain tumor

Not all brain tumors reveal themselves in the same way. If a tumor is very small, for instance, you may not experience any symptoms, or the symptoms might be so insignificant you won’t notice them. As the tumor becomes larger, however, location plays a role in which of the many symptoms you may experience. When a tumor puts pressure on the visual processing area of the brain — what’s known as the occipital lobe — the result can be blurry vision, among other changes to your eyesight.

Detached retina

​The retina is a structure at that back of the eye that has photoreceptors that help us to perceive color and provide central vision. When the retina pulls away from the layer of tissue at the back of the eye, the result is one or more vision-threatening symptoms, including flashing lights, floaters — and the sudden onset of blurred vision. “A retinal detachment is a condition associated with rapid and severe vision loss because often the entirety of the retina is affected in a short period of time,” says Andreoli. Getting treatment right away can reduce your risk for permanent vision loss. 

Closed-angle glaucoma

Your eyes are filled with two substances that help keep them healthy. Glaucoma occurs when one of these substances, the gel-like vitreous humor, isn’t able to drain properly and causes pressure to build up. Unlike open-angle glaucoma, the far more common form of the disease, in which pressure builds up slowly over time, closed-angle glaucoma tends to come on suddenly. The buildup of pressure on the optic nerve can cause permanent damage and vision loss and is considered a medical emergency. This type of glaucoma is more likely to occur in one eye and puts you at a higher risk of developing it in the other eye.​

Age-related macular degeneration (AMD)

Blurriness, wavy or crooked lines or even blank spots in your central vision can be a sign of AMD, a progressive eye disease that damages the macula, the part of the eye that controls straight-ahead vision. It can affect one or both eyes. And while dry AMD, the far more common form of the disease, comes on gradually, that’s not so with wet AMD. Blurry or distorted vision that comes on quickly is a classic sign of wet AMD.

Can dehydration cause blurry vision?

Yes, indirectly. Dehydration, which is common among older people, can lead to renal, cognitive and metabolic problems. It can also lead to a common eye condition called dry eye syndrome, “one of the most common causes of blurry vision,” says Andreoli. Making matters worse, “significant dehydration can lead to decreases in blood pressure, which can also be associated with some of the more rapid vision changes.” 

When should I go to the doctor for blurry vision in one eye? 

Blurry vision in one eye can be a symptom of conditions ranging from the serious to the not so serious — and a few in between — making it hard to know when to seek medical care. The best clue you should call your eye doctor immediately is the most obvious one: The blurred vision came on suddenly.

“Anytime a patient is aware of an abrupt vision change — pain in the eye, redness, new flashing lights or new floaters — [they] should immediately seek care from their ophthalmologist, as these can be indications of conditions that may be permanently vision threatening,” says Andreoli. 

How to fix one blurry eye?  

Treatment depends on the cause. “Sudden-onset eye emergencies from a known cause are treated more urgently,” says Usiwoma Abugo, M.D., spokesperson for the American Academy of Ophthalmology and an ophthalmologist at Katzen Eye Group in Lutherville, Maryland. “For example, if it’s caused by severe high blood pressure, interventions will be taken to rapidly restore eye health and overall health by reducing blood pressure. The same will be done for abnormal blood sugars or abnormally high cholesterol.” ​​If, on the other hand, the blurriness in one eye came on gradually, the treatment will be addressed by your ophthalmologist over a series of visits. Take, for instance, “the gradual onset of blurred vision from a cataract, something that is commonly related to normal aging,” says Abugo. “A cataract, which is a clouding of the lens of the eye, needs to be assessed by an eye surgeon or ophthalmologist, but it’s not frequently related to a life-threatening systemic condition.”