What is blurred vision in one eye? Blurred vision in one eye is a loss of visual acuity that affects only one eye. Blurred vision in one eye can be due to a number of different conditions. It may result from simple, harmless causes, such as discharge from the eyes or crying, or it may result from serious causes such as brain damage that involves one of the optic nerves. In many cases, blurred vision, whether in one or both eyes, is caused by refractive error such as nearsightedness or farsightedness, which can be corrected with the right eyeglasses or contact lenses. Depending on the cause, blurred vision in one eye may affect your ability to resolve objects at a specific distance or at any distance. Cloudy vision, caused by loss of transparency in your lens or cornea, is sometimes called blurred vision. In rare cases, blurred vision in one eye may indicate a disorder in the brain or central nervous system, such as a brain tumor that presses on one of the optic nerves. Because your eyes and vision are vital to your quality of life, be sure to contact your health care provider if you have blurred vision in one eye or any other eye symptoms. Occasionally, blurred vision can be a sign of a medical emergency. Seek immediate medical care (call 911) if you experience blurred vision along with other serious symptoms such as a sudden change in vision, loss of vision, severe eye pain, sudden weakness or numbness on one side of the body, or a change in level of consciousness or alertness. Seek prompt medical care if your symptom of blurred vision in one eye is persistent, recurrent, or causes you concern.