Blurred vision

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Blurred vision is a lack of sharpness in vision, resulting in the inability to see fine details. It can be a symptom of various conditions, both minor and severe, and can affect one or both eyes.

Definition

Blurred vision is characterized by the loss of visual acuity, making objects appear out of focus and hazy. It differs from double vision, where two distinct images of a single object are seen, and distorted vision, where objects may look warped or misshapen.

Causes

Blurred vision can be a result of various factors, including:

• Refractive Errors: These are the most common causes and include myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia (age-related focus dysfunction).
• Eye Conditions: Such as cataracts, glaucoma, macular degeneration, and retinal detachment.
• Eye Infections or Injuries: Conjunctivitis or corneal abrasion can lead to temporary blurred vision.
• Dry Eyes: Insufficient tear production can cause blurred vision.
• Medications: Some medications list blurred vision as a potential side effect.
• Systemic Diseases: Diabetes, hypertension, and migraine can have visual symptoms including blurriness.
• Pregnancy: Hormonal changes during pregnancy can alter the shape and thickness of the cornea, leading to temporary blurred vision.

Symptoms and Complications

Blurred vision may be accompanied by other symptoms depending on its cause. These might include:

• Eye pain or discomfort
• Redness or discharge
• Sensitivity to light
• Headaches
• Nausea

Complications can arise if the underlying cause is not addressed. For instance, untreated refractive errors can lead to strabismus (crossed eyes) or amblyopia (lazy eye) in children.

Diagnosis

A comprehensive eye examination by an optometrist or ophthalmologist is necessary to determine the cause of blurred vision. This may involve:

• Visual Acuity Test: Using a Snellen chart to measure sharpness of vision.
• Refraction Test: To determine the appropriate lens power needed to compensate for any refractive error.
• Slit Lamp Examination: To inspect the anterior segment of the eye.
• Dilated Eye Examination: To provide a clearer view of the retina and optic nerve.

In cases where systemic diseases are suspected, further medical tests might be recommended.

Treatment

Treatment largely depends on the identified cause of blurred vision:

• Corrective Lenses: For refractive errors.
• Medications: Such as antibiotics for infections or eye drops for dry eyes.
• Surgery: Procedures like LASIK for refractive errors, or cataract surgery to replace a cloudy lens.
• Managing Underlying Conditions: For systemic diseases, adequate control and management can alleviate visual symptoms.

Prevention

Regular eye examinations can help detect and address potential causes of blurred vision before they become severe. Additionally, protecting the eyes from injury, using appropriate lighting, and taking breaks when doing close-up work can help in preventing blurred vision.

Causes

There are many causes of blurred vision:

• Use of atropine or other anticholinergics

• Presbyopia—Difficulty focusing on objects that are close. Common in the elderly. (Accommodation tends to decrease with age.)

• Cataracts—Cloudiness over the eye's lens, causing poor night-time vision, halos around lights, and sensitivity to glare. Daytime vision is eventually affected. Common in the elderly.

• Glaucoma—Increased pressure in the eye, causing poor night vision, blind spots, and loss of vision to either side. A major cause of blindness. Glaucoma can happen gradually or suddenly—if sudden, it is a medical emergency.

• Diabetic retinopathy—This complication of diabetes can lead to bleeding into the retina. Another common cause of blindness.

• Macular degeneration—Loss of central vision, blurred vision (especially while reading), distorted vision (like seeing wavy lines), and colors appearing faded. The most common cause of blindness in people over age 60.

• Eye infection, inflammation, or injury.

• Floaters—Tiny particles drifting across the eye. Although often brief and harmless, they may be a sign of retinal detachment.

• Retinal detachment—Symptoms include floaters, flashes of light across your visual field, or a sensation of a shade or curtain hanging on one side of your visual field.

• Optic neuritis—Inflammation of the optic nerve from infection or multiple sclerosis. You may have pain when you move your eye or touch it through the eyelid.

• Stroke or Transient ischemic attack

• Brain tumor

• Toxocara—A parasitic roundworm that can cause blurred vision

• Bleeding into the eye

• Temporal arteritis—Inflammation of an artery in the brain that supplies blood to the optic nerve.

• Migraine headaches—Spots of light, halos, or zigzag patterns are common symptoms prior to the start of the headache. An ophthalmic migraine is when you have only visual symptoms without a headache.

Blurred vision may be a systemic sign of local anaesthetic toxicity

• Reduced blinking - Lid closure that occurs too infrequently often leads to irregularities of the tear film due to prolonged evaporation, thus resulting in disruptions in visual perception.

See also

• Double vision
• Optic neuritis
• Visual field loss
• Functional visual loss

External links

• Blinzle: to counter impaired refraction caused by a decreased blink rate at a computer

See also

Blurred vision Resources
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