Visual blurring

Visual blurring is a common symptom that refers to the loss of visual acuity with indistinct visual details. It may result from 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 certain drugs.

History

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 the patient has a penetrating or perforating eye injury, don’t touch the eye.

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.

Physical assessment

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. Test visual acuity in both eyes. (See Testing visual acuity, page 691.)

Medical causes

Brain tumor

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

Cataract

A cataract is a painless disorder that causes gradual visual blurring. Other effects of a cataract 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, which causes a concussion, vision may be blurred, double, or temporarily lost. Other findings include changes in LOC and behavior.

Conjunctivitis

With 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 with viral conjunctivitis.

Corneal abrasions

With corneal abrasions, visual blurring may occur with severe eye pain, especially when the eyelid moves over the abrasion. The patient may also have photophobia, redness, and excessive tearing.

Diabetic retinopathy

With diabetic retinopathy, retinal edema and hemorrhage produce gradual blurring, which may progress to blindness. The patient may also have a loss of central vision and color vision.

Eye tumor

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

Glaucoma

With 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 (IOP) may cause nausea and vomiting.

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

Hypertension

Hypertension may cause visual blurring and a constant morning headache that decreases in severity during the day. If diastolic blood pressure exceeds 120 mm Hg, the patient may report a severe, throbbing headache. 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 of hyphemas include moderate pain, diffuse conjunctival injection, visible blood in the anterior chamber, ecchymoses, 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. Assessment reveals a poor pupillary response to light.

Migraine headache

A migraine 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

Blurred vision, diplopia, and paresthesia may occur in the early stages of multiple sclerosis. 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 retinal detachment. Blurring worsens, accompanied by visual floaters and recurring flashes of light. Progressive detachment increases vision loss.

Retinal vein occlusion (central)

Retinal vein occlusion is a painless disorder that causes gradual unilateral visual blurring and varying degrees of vision loss. IOP may be elevated in both eyes.

Senile macular degeneration

Senile macular degeneration may cause painless visual blurring (initially worse at night), loss of central vision and slowly or rapidly progressive vision loss. Vision loss may proceed, eventually affecting both eyes.

Serous retinopathy (central)

With serous retinopathy, visual blurring may accompany darkened vision in the affected eye. The patient may report a blind spot in his visual field and that straight lines appear distorted.

Stroke

Brief attacks of bilateral visual blurring may precede or accompany a stroke. Associated findings include 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, temporal arteritis 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)

Uveitis may produce insidious onset of blurred vision, conjunctival injection, visual floaters, pain, and photophobia. Associated posterior scar formation distorts the shape of the pupil.

Vitreous hemorrhage

Sudden unilateral visual blurring and varying vision loss occur with vitreous hemorrhage. Visual floaters or dark streaks may also occur. The patient may have partial vision with a reddish haze.

Other causes

Drugs

Visual blurring may stem from the effects of cycloplegics, guanethidine, reserpine, clomiphene, phenylbutazone, thiazide diuretics, antihistamines, anticholinergics, or 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.

Pediatric pointers

Visual blurring in children may stem from congenital syphilis, congenital cataracts, refractive errors, eye injuries or infections, and 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 691.) 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.

Patient counseling

As necessary, teach the patient how to instill ophthalmic medication. If visual blurring leads to permanent vision loss, provide emotional support, orient the patient to his surroundings, and provide for his safety. If necessary, prepare him for surgery.

Pictures

Book Source Details

• Book Title: Signs & Symptoms: A 2-in-1 Reference for Nurses
• Author(s): Springhouse
• Year of Publication: 2007
• Copyright Details: Signs & Symptoms: A 2-in-1 Reference for Nurses, Copyright © 2007 Lippincott Williams & Wilkins.

Other Book Chapters Related to Vision changes

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

Copyright Details: Signs & Symptoms: A 2-in-1 Reference for Nurses, Copyright © 2008 Williams & Wilkins.

More About Causes of Vision changes

• Back to symptom: Vision changes: Introduction (review 2085 causes)
• Next Book Extract About Vision changes: Visual floaters (Signs & Symptoms: A 2-in-1 Reference for Nurses)
• All Book Extracts: All Online Book Extracts for Vision changes

More About This Book: Title: Signs & Symptoms: A 2-in-1 Reference for Nurses Authors: Springhouse Publisher: Lippincott Williams & Wilkins Copyright: 2007 ISBN: 1-58255-318-1

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