Blurry vision in one eye can be caused by a variety of factors, ranging from minor issues to serious medical emergencies. Some common causes of blurry vision in one eye include refractive errors, such as nearsightedness, farsightedness, or astigmatism, infections, migraines, cataracts, and dry eye. However, sudden onset or persistent blurry vision in one eye can also be a sign of a serious condition, such as a stroke, retinal detachment, brain tumor, or closed-angle glaucoma. Other symptoms that may accompany blurry vision in one eye and indicate a medical emergency include severe headache, disorientation, difficulty speaking or understanding speech, imbalance or walking issues, numbness or tingling in extremities, flashes of light, many more eye floaters than usual, and vision that resembles a curtain being pulled over the eyes. If you experience sudden onset or persistent blurry vision in one eye, it is important to seek immediate medical attention from an eye doctor or another medical professional to determine the cause and receive appropriate treatment.