Visual blurring

Visual blurring is a common symptom that refers to the loss of visual acuity with indistinct visual details. It may result from an eye injury, a neurologic or eye disorder, or a disorder with vascular complications, such as diabetes mellitus. Visual blurring may also result from mucus passing over the cornea, a refractive error, improperly fitted contact lenses, or the use of certain drugs.

History and physical examination

If your patient has visual blurring accompanied by sudden, severe eye pain, a history of trauma, or sudden vision loss, order an ophthalmologic examination. If he has a penetrating or perforating eye injury, don’t touch the eye. (See Managing sudden vision loss, page 802.)

If the patient isn’t in distress, ask him how long he has had the visual blurring. Does it occur only at certain times? Ask about associated signs and symptoms, such as pain or discharge. If visual blurring followed injury, obtain details of the accident, and ask if vision was impaired immediately after the injury. Obtain a medical and drug history.

Inspect the patient’s eye, noting lid edema, drainage, or conjunctival or scleral redness. Also note an irregularly shaped iris, which may indicate previous trauma, and excessive blinking, which may indicate corneal damage. Assess the patient for pupillary changes, and test visual acuity in both eyes. (See Testing visual acuity, page 803.)

Medical causes

Brain tumor

A brain tumor may cause visual blurring, decreased level of consciousness (LOC), headache, apathy, behavioral changes, memory loss, decreased attention span, dizziness, confusion, aphasia, seizures, ataxia, and signs of hormonal imbalance. Its later effects may include papilledema, vomiting, increased systolic blood pressure, widened pulse pressure, and decorticate posture.

Cataract

This painless disorder causes gradual visual blurring. Other effects include halo vision (an early sign), visual glare in bright light, progressive vision loss, and a gray pupil that later turns milky white.

Concussion

Immediately or shortly after blunt head trauma, the patient may develop blurred, double, or temporarily lost vision. Other findings include changes in LOC and behavior.

Conjunctivitis

Visual blurring may be accompanied by photophobia, pain, burning, tearing, itching, and a feeling of fullness around the eyes. Other findings include redness near the fornices (brilliant red suggests a bacterial cause; milky red, an allergic cause) and drainage (copious, mucopurulent, and flaky in bacterial conjunctivitis; stringy in allergic conjunctivitis). Copious tearing, minimal exudate, and an enlarged preauricular lymph node occur in viral conjunctivitis.

Corneal abrasions

Visual blurring may occur with severe eye pain, photophobia, redness, and excessive tearing.

Corneal dystrophies, hereditary

Visual blurring may remain stable or may progressively worsen throughout life in this disorder. Some corneal dystrophies cause associated pain, vision loss, photophobia, tearing, and corneal opacities.

Corneal foreign bodies

Visual blurring may accompany a foreign-body sensation, excessive tearing, photophobia, intense eye pain, miosis, conjunctival injection, and a dark corneal speck.

Diabetic retinopathy

Retinal edema and hemorrhage produce gradual blurring, which may progress to blindness.

Dislocated lens

Dislocation of the lens, especially beyond the line of vision, causes visual blurring and (with trauma) redness.

Eye tumor

If the tumor involves the macula, visual blurring may be the presenting symptom. Related findings include varying visual field losses.

Glaucoma

In acute angle-closure glaucoma, an ocular emergency, unilateral visual blurring and severe pain begin suddenly. Other findings include halo vision; a moderately dilated, nonreactive pupil; conjunctival injection; a cloudy cornea; and decreased visual acuity. Severely elevated intraocular pressure may cause nausea and vomiting.

In chronic angle-closure glaucoma, transient visual blurring and halo vision may precede pain and blindness.

Hypertension

This disorder may cause visual blurring and a throbbing morning headache that decreases in severity during the day. However, if diastolic blood pressure exceeds 120 mm Hg, the headache may persist. Associated findings include restlessness, confusion, nausea, vomiting, seizures, and decreased LOC.

Hyphema

Blunt eye trauma with hemorrhage into the anterior chamber causes visual blurring. Other effects include moderate pain, diffuse conjunctival injection, visible blood in the anterior chamber, ecchymosis, eyelid edema, and a hard eye.

Iritis

Acute iritis causes sudden visual blurring, moderate to severe eye pain, photophobia, conjunctival injection, and a constricted pupil.

Migraine headache

This disorder may cause visual blurring and paroxysmal attacks of severe, throbbing, unilateral or bilateral headache. Other effects include nausea, vomiting, sensitivity to light and noise, and sensory or visual auras.

Multiple sclerosis (MS)

Blurred vision, diplopia, and paresthesia may occur in the early stages of MS. Later effects vary and may include nystagmus, muscle weakness, paralysis, spasticity, hyperreflexia, intention tremor, and ataxic gait. Urinary frequency, urgency, and incontinence may also occur.

Optic neuritis

Inflammation, degeneration, or demyelinization of the optic nerve usually causes an acute attack of visual blurring and vision loss. Related findings include scotomas and eye pain. Ophthalmoscopic examination reveals hyperemia of the optic disk, large vein distention, blurred disk margins, and filling of the physiologic cup.

Retinal detachment

Sudden visual blurring may be the initial symptom of a detached retina. Other effects include visual floaters and recurring flashes of light. As the detachment progresses, the patient experiences gradual vision loss, likened to a curtain covering the visual field.

Retinal vein occlusion (central)

This disorder causes gradual unilateral visual blurring and varying degrees of vision loss.

Senile macular degeneration

This retinal disorder may cause visual blurring (initially worse at night) and slowly or rapidly progressive vision loss.

Serous retinopathy (central)

Visual blurring may accompany darkened vision in the affected eye.

Stroke

Brief attacks of bilateral visual blurring may precede or accompany a stroke. Associated findings include a decreased LOC, contralateral hemiplegia, dysarthria, dysphagia, ataxia, unilateral sensory loss, and apraxia. Stroke may also cause agnosia, aphasia, homonymous hemianopia, diplopia, disorientation, memory loss, and poor judgment. Other features include urine retention or urinary incontinence, constipation, personality changes, emotional lability, headache, vomiting, and seizures.

Temporal arteritis

Most common in women older than age 60, this disorder causes sudden blurred vision accompanied by vision loss and a throbbing unilateral headache in the temporal or frontotemporal region. Prodromal signs and symptoms include malaise, anorexia, weight loss, weakness, low-grade fever, and generalized muscle aches. Other findings include confusion; disorientation; swollen, nodular, tender temporal arteries; and erythema of overlying skin.

Uveitis (posterior)

This disorder may produce insidious onset of blurred vision, conjunctival injection, visual floaters, pain, and photophobia.

Vitreous hemorrhage

This condition may cause sudden unilateral visual blurring, varying degrees of vision loss, visual floaters, or dark streaks.

Other causes

Drugs

Visual blurring may stem from the effects of cycloplegics, reserpine, clomiphene, thiazide diuretics, antihistamines, anticholinergics, and phenothiazines.

Special considerations

Prepare the patient for diagnostic tests, such as tonometry, slit-lamp examination, X-rays of the skull and orbit and, if a neurologic lesion is suspected, a computed tomography scan. As necessary, teach him how to instill ophthalmic medication. If visual blurring leads to permanent vision loss, provide emotional support, orient him to his surroundings, and provide for his safety. If necessary, prepare him for surgery.

Pediatric pointers

Visual blurring in children may stem from congenital syphilis, congenital cataracts, refractive errors, eye injuries or infections, or increased intracranial pressure. Refer the child to an ophthalmologist if appropriate.

Test vision in school-age children as you would in adults; test children ages 3 to 6 with the Snellen symbol chart. (See Testing visual acuity, page 803.) Test toddlers with Allen cards, each illustrated with a familiar object such as an animal. Ask the child to cover one eye and identify the objects as you flash them. Then ask him to identify them as you gradually back away. Record the maximum distance at which he can identify at least three pictures.

Book Source Details

• Book Title: Professional Guide to Signs & Symptoms (Fifth Edition)
• Author(s): Springhouse
• Year of Publication: 2006
• Copyright Details: Professional Guide to Signs & Symptoms (Fifth Edition), Copyright © 2006 Lippincott Williams & Wilkins.

Other Book Chapters Related to Vision changes

Read excerpts from these other book chapters related to Vision changes:

Copyright Details: Professional Guide to Signs & Symptoms (Fifth Edition), Copyright © 2008 Williams & Wilkins.

More About Causes of Vision changes

• Back to symptom: Vision changes: Introduction (review 2057 causes)
• Next Book Extract About Vision changes: Visual floaters (Professional Guide to Signs & Symptoms (Fifth Edition))
• All Book Extracts: All Online Book Extracts for Vision changes

More About This Book: Title: Professional Guide to Signs & Symptoms (Fifth Edition) Authors: Springhouse Publisher: Lippincott Williams & Wilkins Copyright: 2006 ISBN: 1-58255-510-9

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