Some Causes and Features of Blurred Vision
Cause |
Common Features* |
Diagnosis† |
Clouding of normally transparent eye structures |
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Symptoms that begin gradually Loss of the ability to distinguish between light and dark (loss of contrast) and glare (seeing halos and star bursts around lights) Often in people with risk factors (such as older age or use of corticosteroids) |
A doctor's examination |
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Corneal scarring after an injury or an infection |
Usually in people with a previous injury or infection |
A doctor's examination |
Disorders that affect the retina |
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Usually symptoms that begin gradually Loss of central vision (what a person is looking at directly) much more than peripheral vision (what is seen out of the corner of the eye) |
Sometimes an eye imaging test |
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Infection of the retina (as may be caused by cytomegalovirus or Toxoplasma parasites) |
Usually in people who have HIV infection or another disorder that weakens the immune system Often eye redness or pain |
Tests to check for organisms suspected to be causing the infection |
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Retinitis pigmentosa (progressive deterioration of the retina) |
Symptoms that begin gradually Primarily night blindness |
Specialized testing (such as measuring the retina's responses to light in various conditions), done by an ophthalmologist |
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Retinopathy (damage of the retina) associated with a bodywide disorder such as high blood pressure (see hypertensive retinopathy), systemic lupus erythematosus (lupus), diabetes (see diabetic retinopathy), Waldenström macroglobulinemia, and multiple myeloma or other disorders that can cause thickening of the blood (hyperviscosity syndrome) |
Often in people known to have such disorders Usually other symptoms in addition to loss of vision |
Tests to check for disorders suspected to be causing retinopathy |
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Risk factors (for example, diabetic retinopathy, uveitis, retinal detachment or ocular injury) Blurry or distorted vision (eg, straight lines appear wavy) |
Ophthalmoscopy (using an instrument to painlessly look inside the eye) |
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Macular hole |
Blurry vision initially in straight vision |
Ophthalmoscopy (using an instrument to painlessly look inside the eye) Optical coherence tomography (specialized imaging of the back of the eye) |
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Risk factors (for example, hypertension, age, glaucoma) Painless vision loss (usually sudden) Sometimes, blurry vision |
Ophthalmoscopy (using an instrument to painlessly look inside the eye) Sometimes, fluorescein angiography (using a fluorescent dye to take images of the back of the eye) Sometimes, optical coherence tomography (specialized imaging of the back of the eye) |
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Disorders that affect the optic nerve or its connections in the brain |
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Missing stairs and not seeing parts of written or typed words |
Measurement of pressure inside the eye (tonometry), examination of the angles between eye structures such as the cornea and iris (gonioscopy), and optic nerve testing, done by an ophthalmologist |
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Optic neuritis (inflammation of the optic nerve), which can be related to multiple sclerosis |
Usually mild pain that may worsen when one eye (often) or both eyes are moved Partial or complete loss of vision Symptoms that can become severe in hours or days No effect on the eyelids and cornea |
Often MRI with contrast |
Disorders that affect focus |
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Refractive errors (such as nearsightedness, farsightedness, and astigmatism) |
Sharpness of vision (visual acuity) that varies with distance from objects Decreased acuity that can be corrected by using glasses or a pinhole device |
Testing of refraction by an optometrist or ophthalmologist |
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* Features include symptoms and the results of the doctor's examination. Features mentioned are typical but not always present. † Although a doctor's examination is always done, it is only mentioned in this column if the diagnosis can be made only by the doctor's examination, without any testing. HIV = human immunodeficiency virus; MRI = magnetic resonance imaging. |
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