Blurred Vision: Causes

What causes blurred vision?

Blurred vision is caused by a variety of mild to serious diseases, disorders and conditions. While many cases of blurred vision are due to problems with the eyes, blurred vision can also be due to neurological and autoimmune disorders. Many of the causes are very serious medical conditions.

Optical or eye-related causes of blurred vision

Blurred vision can be caused by several kinds of common vision problems:

• Astigmatism (when light rays do not focus clearly at one point on the retina due to the unequal curvature of the surface of the eye)

• Dry eyes

• Eye irritation

• Farsightedness (hyperopia, when eyes focus better on distant objects than near objects)

• Nearsightedness (myopia, when eyes focus better on near objects than distant objects)

• Presbyopia (a normal, gradual loss of your eyes’ ability to focus on near objects due to aging)

• Wrong prescription for eyeglasses or contact lenses

Diseases and conditions of the eye can lead to blurred vision

Several different diseases, disorders and conditions that cause blurry vision include:

• Cataracts

• Conjunctivitis (inflammation of the eye surface)

• Corneal ulcer

• Eye inflammation or infection

• Glaucoma (where fluid pressure builds up in the eye, including narrow angle glaucoma and acute angle glaucoma)

• Macular degeneration (condition that causes blurring of the central vision)

• Optic neuritis (inflammation of the optic nerve)

• Retinal detachment (detachment of the light-sensing layer inside your eye from the blood vessels that provide it oxygen and nutrients)

• Retinal vessel occlusion (blockage of the blood vessels of the eye)

• Retinoblastoma (cancer of the retina)

• Retinopathy and diabetic lens osmosis (complications of diabetes)

• Uveitis and iritis (inflammation of the uvea)

Autoimmune causes of blurred vision

Some autoimmune diseases result in blurred vision including:

• Multiple sclerosis (disease that affects the brain and spinal cord causing weakness, coordination, balance difficulties, and other problems)

• Myasthenia gravis (autoimmune neuromuscular disorder that causes muscle weakness)

• Systemic lupus erythematosus (disorder in which the body attacks its own healthy cells and tissues)

Other causes of blurred vision

Various other diseases, disorders and conditions that cause blurred vision include:

• Amphetamines and other illicit drugs

• Anemia

• Concussion

• Migraine

• Pregnancy

• Sarcoidosis (inflammatory disease most commonly affecting the lungs, skin and eyes)

• Temporal arteritis (inflammation of blood vessels in the head)

• Transient ischemic attack (also known as TIA, temporary stroke-like symptoms that may be a warning sign of an impending stroke)

Life-threatening causes of blurred vision

In some cases, blurred vision may be a symptom of a serious or life-threatening condition that should be immediately evaluated in an emergency setting. These include:

• Atherosclerotic emboli (plaque that travels to the brain and can cause a stroke)

• Botulism

• Brain hemorrhage (bleeding in the brain)

• Brain tumor

• Carotid embolism

• Encephalitis (inflammation and swelling of the brain due to a viral infection or other causes)

• Head injury

• Stroke

• Vertebrobasilar insufficiency

What are the potential complications of blurred vision?

Blurred vision complications depend on the underlying disease, disorder or condition. Complications of untreated or poorly controlled blurred vision can be serious and even life threatening. A delay in treating a vision problem can lead to loss of sight, such as with glaucoma, an eye injury, or retinal detachment, or loss of life, such as with stroke or brain hemorrhage. Even temporary blurry vision can result from serious conditions, such as stroke, transient ischemic attack (TIA), hypertension, epilepsy or migraine. Over time, blurred vision and the underlying cause of blurred vision can lead to serious complications including:

• Brain damage

• Loss of sight (blindness)

• Loss of the eye and orbit (bony part surrounding the eye globe)