Blurry eyesight, which is the loss of vision sharpness and the inability to see small details, is caused by many things. Various eye conditions cause blurry eyesight, most of which are easily treated. The most common causes of blurry eyesight include myopia, hyperopia, macular degeneration, astigmatism, cataracts and glaucoma. Certain medical conditions and some lifestyle habits might also cause vision to blur.
The most common eye condition resulting in blurry eyesight is myopia, which is also called nearsightedness. When the cornea of the eye becomes too curved, it is not able to correctly focus light onto the lens of the eye. The result is that objects in the distance appear out of focus and blurry.
Hyperopia, or farsightedness, is the opposite of myopia and is also very common. With this condition, the eye is able to see far distances clearly but blurs objects up close. Both conditions can be improved with glasses, contact lenses or eye surgery. Sometimes even changes in nutrition, habit or lifestyle can improve vision.
Macular degeneration is a serious eye condition that might also cause blurry vision. This condition cannot be corrected with glasses because it is caused by the loss of light-detecting neurons at the back of the eye. Macular degeneration is prevalent in the elderly and is likely to cause eventual blindness.
Astigmatism is a condition caused by an irregularly shaped cornea or lens. It causes vision to be out of focus and blurry because the optics of the eye are unable to refract light correctly. Someone with astigmatism might also suffer from other vision problems, such as myopia, hyperopia and eye strain, as well as headaches.
Cataracts, a clouding of the crystalline lens of the eye, and glaucoma, an increased pressure in the eye, are common eye conditions that might also cause blurry vision. If left untreated, these conditions could worsen, resulting in permanent vision loss. Dry eyes, eye infections, inflammation and eye injury might also cause vision to blur.
Certain medical conditions might trigger blurry eyesight. Some people experience temporary blurry eyesight when they have a cold or viral infection. Sufferers of migraine headaches often experience blurry vision prior to or during a headache. Blurred eyesight might follow a stroke or result from a brain tumor. People who have severely high blood pressure might experience blurry vision on occasion.
Some lifestyle habits cause blurry eyesight as well. Overindulgence in alcohol causes vision to blur, as does the consumption of various illegal drugs. Many people experience blurred vision after prolonged use of a computer, television or video gaming system. Lack of sleep and exhaustion might also cause vision to blur temporarily.
Blurry vision that is related to an eye problem is usually treated with glasses, lenses, eye drops or laser eye surgery. Blurry eyesight might also be a sign of another illness or condition. Any changes in vision, including blurry eyesight, should always be evaluated by a medical professional.