Acute Vision Loss: A Merck Manual of Patient Symptoms podcast

Loss of vision is usually considered acute if it develops within a few minutes to a couple of days. It may affect one or both eyes and all or part of a visual field. Patients with small visual field defects (eg, caused by a small retinal detachment) may describe their symptoms as blurred vision.

Pathophysiology

Acute loss of vision has 3 general causes:

• Opacification of normally transparent structures through which light rays pass to reach the retina (eg, cornea, vitreous)
• Retinal abnormalities
• Abnormalities affecting the optic nerve or visual pathways

Etiology

The most common causes of acute loss of vision are

• Vascular occlusions of the retina (central retinal artery occlusion, central retinal vein occlusion)
• Ischemic optic neuropathy (often in patients with temporal arteritis)
• Vitreous hemorrhage (caused by diabetic retinopathy or trauma)
• Trauma

In addition, sudden recognition of loss of vision (pseudo-sudden loss of vision) may manifest initially as sudden onset. For example, a patient with long-standing reduced vision in one eye (possibly caused by a dense cataract) suddenly is aware of the reduced vision in the affected eye when covering the unaffected eye.

Presence or absence of pain helps categorize loss of vision (see Table 1: Symptoms of Ophthalmologic Disorders: Some Causes of Acute Vision Loss).

Most disorders that cause total loss of vision when they affect the entire eye may affect only part of the eye and cause only a visual field defect (eg, branch occlusion of the retinal artery or retinal vein, focal retinal detachment).

Table 1
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Some Causes of Acute Vision Loss Cause Suggestive Findings Diagnostic Approach Acute loss of vision without eye pain Arteritic ischemic optic neuropathy (usually in patients with giant cell [temporal] arteritis) Sometimes headache, jaw or tongue claudication, temporal artery tenderness or swelling, pale and swollen disk with surrounding hemorrhages, occlusion of retinal artery or its branches Sometimes proximal myalgias with stiffness (due to polymyalgia rheumatica) ESR Temporal artery biopsy Functional loss of vision Normal pupillary light reflexes, positive optokinetic nystagmus, no objective abnormalities on eye examination Often inability to write name or bring outstretched hands together Sometimes indifferent affect despite severity of claimed loss of vision Clinical evaluation If diagnosis is in doubt, ophthalmologic evaluation and visual evoked responses Macular hemorrhage due to neovascularization in age-related macular degeneration Blood within or deep to retina in and around the macula Clinical evaluation Nonarteritic ischemic optic neuropathy Optic disk edema and hemorrhages Sometimes loss of inferior and central visual fields Risk factors (eg, diabetes, hypertension, hypotensive episode) ESR Consideration of temporal artery biopsy to exclude giant cell arteritis Ocular migraine Scintillating scotomata, mosaic patterns, or complete loss of vision lasting usually 10–60 min and often followed by headache Often in young patients Clinical evaluation Retinal artery occlusion Nearly instantaneous onset, pale retina, cherry-red fovea, sometimes Hollenhorst plaque (refractile object at the site of arterial occlusion) Risk factors for vascular disease ESR to exclude giant cell arteritis Retinal detachment Recent increase in floaters, photopsias (flashing lights), or both Visual field defect, retinal folds Risk factors (eg, trauma, eye surgery, severe myopia; in men, advanced age) Clinical evaluation Retinal vein occlusion Frequent, multiple, widely distributed retinal hemorrhages Risk factors (eg, diabetes, hypertension, hyperviscosity syndrome, sickle cell anemia) Clinical evaluation Transient ischemic attack or stroke Bilaterally symmetric (homonymous) field defects, no effect on visual acuity in the intact parts of the visual field (bilateral occipital lesions are the exception and are uncommon but can occur due to basilar artery occlusion) Risk factors for atherosclerosis Consideration of MRI or CT Carotid ultrasonography ECG Continuous monitoring of cardiac rhythm Vitreous hemorrhage Previous floaters or spider web in vision Risk factors (eg, diabetes, retinal tear, sickle cell anemia, trauma) Possible ultrasonography to assess retina Acute loss of vision with eye pain Acute angle-closure glaucoma Halos around lights, nausea, headache, photophobia, conjunctival injection, corneal edema, shallow anterior chamber, intraocular pressure usually > 40 Immediate ophthalmologic evaluation Gonioscopy Corneal ulcer Ulcer visible with fluorescein staining, slit-lamp examination, or both Risk factors (eg, injury, contact lens use, herpetic [painful vesicular] rash in V1 distribution) Ophthalmologic evaluation Endophthalmitis Floaters, conjunctival injection, decreased red reflex, hypopyon, or a combination Risk factors (such as history of traumatic ruptured globe or intraocular foreign body [eg, after hammering metal on metal], injury during eye surgery) Immediate ophthalmologic evaluation with cultures of anterior chamber and vitreous fluids Optic neuritis (usually painful but not always) Mild pain with eye movement, afferent pupillary defect (occurs early) Central or peripheral visual field defects Abnormal color vision testing results Sometimes optic disk edema Gadolinium-enhanced MRI to diagnose multiple sclerosis V1 = ophthalmic division of the trigeminal nerve. Some Causes of Acute Vision Loss Cause Suggestive Findings Diagnostic Approach Acute loss of vision without eye pain Arteritic ischemic optic neuropathy (usually in patients with giant cell [temporal] arteritis) Sometimes headache, jaw or tongue claudication, temporal artery tenderness or swelling, pale and swollen disk with surrounding hemorrhages, occlusion of retinal artery or its branches Sometimes proximal myalgias with stiffness (due to polymyalgia rheumatica) ESR Temporal artery biopsy Functional loss of vision Normal pupillary light reflexes, positive optokinetic nystagmus, no objective abnormalities on eye examination Often inability to write name or bring outstretched hands together Sometimes indifferent affect despite severity of claimed loss of vision Clinical evaluation If diagnosis is in doubt, ophthalmologic evaluation and visual evoked responses Macular hemorrhage due to neovascularization in age-related macular degeneration Blood within or deep to retina in and around the macula Clinical evaluation Nonarteritic ischemic optic neuropathy Optic disk edema and hemorrhages Sometimes loss of inferior and central visual fields Risk factors (eg, diabetes, hypertension, hypotensive episode) ESR Consideration of temporal artery biopsy to exclude giant cell arteritis Ocular migraine Scintillating scotomata, mosaic patterns, or complete loss of vision lasting usually 10–60 min and often followed by headache Often in young patients Clinical evaluation Retinal artery occlusion Nearly instantaneous onset, pale retina, cherry-red fovea, sometimes Hollenhorst plaque (refractile object at the site of arterial occlusion) Risk factors for vascular disease ESR to exclude giant cell arteritis Retinal detachment Recent increase in floaters, photopsias (flashing lights), or both Visual field defect, retinal folds Risk factors (eg, trauma, eye surgery, severe myopia; in men, advanced age) Clinical evaluation Retinal vein occlusion Frequent, multiple, widely distributed retinal hemorrhages Risk factors (eg, diabetes, hypertension, hyperviscosity syndrome, sickle cell anemia) Clinical evaluation Transient ischemic attack or stroke Bilaterally symmetric (homonymous) field defects, no effect on visual acuity in the intact parts of the visual field (bilateral occipital lesions are the exception and are uncommon but can occur due to basilar artery occlusion) Risk factors for atherosclerosis Consideration of MRI or CT Carotid ultrasonography ECG Continuous monitoring of cardiac rhythm Vitreous hemorrhage Previous floaters or spider web in vision Risk factors (eg, diabetes, retinal tear, sickle cell anemia, trauma) Possible ultrasonography to assess retina Acute loss of vision with eye pain Acute angle-closure glaucoma Halos around lights, nausea, headache, photophobia, conjunctival injection, corneal edema, shallow anterior chamber, intraocular pressure usually > 40 Immediate ophthalmologic evaluation Gonioscopy Corneal ulcer Ulcer visible with fluorescein staining, slit-lamp examination, or both Risk factors (eg, injury, contact lens use, herpetic [painful vesicular] rash in V1 distribution) Ophthalmologic evaluation Endophthalmitis Floaters, conjunctival injection, decreased red reflex, hypopyon, or a combination Risk factors (such as history of traumatic ruptured globe or intraocular foreign body [eg, after hammering metal on metal], injury during eye surgery) Immediate ophthalmologic evaluation with cultures of anterior chamber and vitreous fluids Optic neuritis (usually painful but not always) Mild pain with eye movement, afferent pupillary defect (occurs early) Central or peripheral visual field defects Abnormal color vision testing results Sometimes optic disk edema Gadolinium-enhanced MRI to diagnose multiple sclerosis V1 = ophthalmic division of the trigeminal nerve.

Less common causes of acute loss of vision include

• Anterior uveitis (a common disorder, but one that usually causes eye pain severe enough to trigger evaluation before vision is lost)
• Highly aggressive retinitis
• Certain drugs (eg, methanol, salicylates, ergot alkaloids, quinine)

Evaluation

History

History of present illness should describe loss of vision in terms of onset, duration, progression, and location (whether it is monocular or binocular and whether it involves the entire visual field or a specific part and which part). Important associated visual symptoms include floaters, flashing lights, halos around lights, distorted color vision, and jagged or mosaic patterns (scintillating scotomata). The patient should be asked about eye pain and whether it is constant or occurs only with eye movement.

Review of systems should seek extraocular symptoms of possible causes, including jaw or tongue claudication, temporal headache, proximal muscle pain, and stiffness (giant cell arteritis); and headaches (ocular migraine).

Past medical history should seek known risk factors for eye disorders (eg, contact lens use, severe myopia, recent eye surgery or injury), risk factors for vascular disease (eg, diabetes, hypertension), and hematologic disorders (eg, sickle cell anemia or disorders such as Waldenström macroglobulinemia or multiple myeloma that could cause a hyperviscosity syndrome).

Family history should note any family history of migraine headaches.

Physical examination

Vital signs, including temperature, are measured.

If the diagnosis of a transient ischemic attack is under consideration, a complete neurologic examination is done. The facial skin is inspected for vesicles or ulcers in the V₁ distribution (ophthalmic division of the trigeminal nerve), and the temples are palpated for pulses, tenderness, or nodularity over the course of the temporal artery. However, most of the examination focuses on the eye.

Eye examination includes the following:

• Visual acuity is measured.
• Peripheral visual fields are assessed by confrontation.
• Central visual fields are assessed by Amsler grid.
• Direct and consensual pupillary light reflexes are examined using the swinging flashlight test.
• Ocular motility is assessed.
• Color vision is tested with color plates.
• The eyelids, sclera, and conjunctiva are examined using a slit lamp if possible.
• The cornea is examined with fluorescein staining.
• The anterior chamber is examined for cells and flare in patients who have eye pain or conjunctival injection.
• The lens is checked for cataracts using a direct ophthalmoscope, slit lamp, or both.
• Intraocular pressure is measured.
• Ophthalmoscopy is done, preferably after dilating the pupil with a drop of a sympathomimetic (eg, 2.5% phenylephrine), cycloplegic (eg, 1% cyclopentolate or 1% tropicamide), or both; dilation is nearly full after about 20 min. The entire fundus, including the retina, macula, fovea, vessels, and optic disk and its margins, is examined.
• If pupillary light responses are normal and functional loss of vision is suspected (rarely), optokinetic nystagmus is checked. If an optokinetic drum is unavailable, a mirror can be held near the patient's eye and slowly moved. If the patient can see, the eyes usually track movement of the mirror.

Red flags

Acute loss of vision is itself a red flag; most causes are serious.

Interpretation of findings

Diagnosis can be begun systematically. Fig. 1: Symptoms of Ophthalmologic Disorders: Evaluation of acute vision loss. describes a simplified, general approach. Specific patterns of visual field deficit help suggest a cause (see Table 1: Approach to the Ophthalmologic Patient: Types of Field Defects ). Other clinical findings also help suggest a cause (see Table 1: Symptoms of Ophthalmologic Disorders: Some Causes of Acute Vision Loss):

• Difficulty seeing the red reflex during ophthalmoscopy suggests opacification of transparent structures (eg, caused by corneal ulcer, vitreous hemorrhage, or severe endophthalmitis).
• Retinal abnormalities that are severe enough to cause acute loss of vision are detectable during ophthalmoscopy, particularly if the pupils are dilated. Retinal detachment may show retinal folds; retinal vein occlusion may show marked retinal hemorrhages; and retinal artery occlusion may show pale retina with a cherry-red fovea.
• An afferent pupillary defect (absence of a direct pupillary light response but a normal consensual response) with an otherwise normal examination (except sometimes an abnormal optic disk) suggests an abnormality of the optic nerve or retina (ie, anterior to the chiasm).

In addition, the following facts may help:

• Monocular symptoms suggest a lesion anterior to the optic chiasm.
• Bilateral, symmetric (homonymous) visual field defects suggest a lesion posterior to the chiasm.
• Constant eye pain suggests a corneal lesion (ulcer or abrasion), anterior chamber inflammation, or increased intraocular pressure, whereas eye pain with movement suggests optic neuritis.
• Temporal headaches suggest giant cell arteritis or migraine.

Fig. 1
Evaluation of acute vision loss.

Testing

ESR is done for all patients with symptoms (eg, temporal headaches, jaw claudication, proximal myalgias, stiffness) or signs (eg, temporal artery tenderness or induration, pale retina, papilledema) suggesting optic nerve or retinal ischemia to exclude giant cell arteritis.

Other testing is listed in Table 1: Symptoms of Ophthalmologic Disorders: Some Causes of Acute Vision Loss. The following are of particular importance:

• Ultrasonography is done to view the retina if the retina is not clearly visible with pupillary dilation and indirect ophthalmoscopy done by an ophthalmologist.
• Gadolinium-enhanced MRI is done for patients who have eye pain with movement or afferent pupillary defect, particularly with optic nerve swelling on ophthalmoscopy, to diagnose multiple sclerosis.

Treatment

Causative disorders are treated. Treatment should usually commence immediately if the cause is treatable. In many cases (eg, vascular disorders), treatment is unlikely to salvage the affected eye but can decrease the risk of the same process occurring in the contralateral eye or of a complication caused by the same process (eg, ischemic stroke).

Key Points

• Diagnosis and treatment should occur as rapidly as possible.
• Acute monocular loss of vision with an afferent pupillary defect indicates a lesion of the eye or of the optic nerve anterior to the optic chiasm.
• Optic nerve lesion, particularly ischemia, is considered in patients with acute monocular loss of vision or afferent pupillary defect and in those with or without optic nerve abnormalities on ophthalmoscopy but no other abnormalities on eye examination.
• Corneal ulcer, acute angle-closure glaucoma, endophthalmitis, or severe anterior uveitis is considered in patients with acute monocular loss of vision, afferent pupillary defect, eye pain, and conjunctival injection.

Last full review/revision November 2012 by Kathryn Colby, MD, PhD