Blurry vision is the loss of sharpness of eyesight, making objects appear out of focus and hazy. The primary causes of blurred vision are refractive errors – nearsightedness, farsightedness and astigmatism – or presbyopia. But blurry vision also can be a symptom of more serious problems, including a potentially sight-threatening eye disease or neurological disorder. A qualified eye doctor can measure the extent of your blurred vision and determine the cause with a comprehensive eye exam. Sudden blurry vision that persists could be a sign of a serious health problem, and you should see a doctor immediately.
Causes of Blurry Vision
Myopia or Hyperopia
Blurry vision in one eye or both eyes may be a symptom of myopia (nearsighteness), along with squinting, eye strain and headaches. Myopia is the most common refractive error and causes objects in the distance to become blurred. Blurred vision from hyperopia (farsightedness) is when distant objects can be seen sharply but your eyes can’t focus properly on close-up objects or doing so causes unusual eye strain and fatigue.
Blurred vision at all distances often is a symptom of astigmatism. A type of refractive error, astigmatism usually is caused by an irregularly shaped cornea. With astigmatism, light rays fail to come to a single focus point on the retina to produce clear vision, regardless of how far away the viewed object is from the eye. Astigmatism, like nearsightedness and farsightedness, can be corrected with eyeglasses, contact lenses or refractive surgery.
If you’re over 40 and beginning to experience blurry vision up close, chances are this is due to the onset of presbyopia, a naturally occurring age – related condition. While the symptoms of presbyopia are the same as those caused by hyperopia (blurry near vision, eye strain when reading), presbyopia is a diminished ability to focus on near objects due to hardening of the lens inside the eye rather than a detect of vision caused by the overall shape of the eye like hyperopia.
Chronic dry eyes
Dry eye syndrome can affect your eyes in numerous ways, including blurred and fluctuating vision. While artificial tears (lubricating eye drops) can help, more advanced dry eyes may need a prescription medication or punctal plugs to keep the eye lubricated and healthy.
Blurry vision is common during pregnancy and sometimes is accompanied by double vision (diplopia). Hormonal changes can alter the shape and thickness of your cornea, causing your vision to blur. Dry eyes also are common in pregnant women and can cause blurred vision. While blurry vision is not always serious, in some cases it could be an indicator of gestational diabetes or high blood pressure.
Vision can be blurred by temporary spots or floaters drifting in our field of vision. Floaters typically appear when the eye’s gel-like vitreous begins to liquefy with age, causing microscopic bits of tissue within the vitreous to float freely inside the eye, casting shadows on the retina. While a normal part of the aging process, if you see a sudden shower of floaters it could signify a torn or detached retina and you should see your eye doctor immediately.
Blurry vision after LASIK
Your vision may be blurry or hazy immediately after LASIK or any other type of refractive surgery. Clarify should improve within a couple of days, but it may take several weeks for your vision to stabilize completely.
Eye drops and medication
Certain eye drops, especially medicated eye drops containing preservatives, can cause irritation and blurry vision. In most cases, these side effects can be controlled with artificial tears, prescription dry eye medication or punctal plugs. Also, some medication such as allergy pills can cause side effects of dry eyes and blurred vision. During a comprehensive eye exam, your optometrist or ophthalmologist can advise you whether any of your medications might cause blurry vision.
Over-wearing contact lenses
Wearing contact lenses for longer than your doctor prescribed will cause proteins and other debris in your film to build up on the lenses. This can cause blurry vision and increase your risk of eye infections.
If symptoms persists, it’s always best to see and consult an eye doctor.