Diagnostic approach to acute vision loss in children

INTRODUCTION — Acute vision loss in children is frightening, not only for the patient and family, but also for the clinician. Blindness, especially if bilateral and permanent, represents a serious loss of function. Unfortunately, children may not present until they have significant loss of vision; very young children will not display declining vision until there is significant compromise and even school-age children compensate well. By the time vision loss is appreciated, the chance for recovery may be low.

The approach to acute vision loss in children will be reviewed here. The approach to vision loss in adults is discussed separately. (See "Approach to the adult with acute persistent visual loss".)

ETIOLOGY — To achieve clear vision, light must follow an unhindered path from the front to the back of the eye, traveling through the cornea, aqueous humor, lens, and vitreous humor to the retina (figure 1). Refracted by the cornea and lens (and perhaps also by glasses or contact lenses), light is focused onto the retina where it is transformed into an electrochemical signal by photoreceptors and supporting cells. The signal is transmitted via the optic nerve through the visual pathways to the occipital lobes.

Alterations in function of any of the structures along the visual pathway may cause vision loss. Pathology can be broadly divided into three major anatomic categories (table 1):

●Visual media problems – Disorders of the cornea, anterior chamber, lens, and vitreous (figure 1)

●Retinal problems – Vascular occlusion, retinal detachment, and retinal tumors

●Neurovisual pathway problems – Optic nerve, chiasmal, and retrochiasmal pathology (figure 2)

Visual media

Open globe — Rupture or laceration of the globe from direct trauma is a common cause of acute vision loss that requires immediate ophthalmologic consultation. Paintball guns, BB guns, projectile toys, scissors, and recreational sharp objects are major culprits. Most victims are male. In many children, the injury is apparent on inspection (picture 1 and picture 2). (See "Open globe injuries: Emergency evaluation and initial management", section on 'Epidemiology'.)

The approach to the patient with an open globe injury is summarized in a rapid overview (table 2). Aggressive examination of the eye is contraindicated when globe rupture is suspected, as forced opening can lead to extrusion of ocular contents. The best course of action before an ophthalmologist can evaluate the child is to protect the eye with a hard shield that avoids pressure on the intraocular contents and to elevate the head of the bed to 30 degrees. Any visible foreign body should be left in place (picture 2). Eye drops should be avoided. An antiemetic (eg, ondansetron) is often prescribed to prevent vomiting and the associated increase in intraocular pressure. Intravenous (IV) pain medications (eg, fentanyl or morphine) and sedation (eg, midazolam or lorazepam) are often needed for pain and to prevent crying. The patient should be kept NPO (nil per os) for possible surgery. (See "Open globe injuries: Emergency evaluation and initial management".)

Chemical burn — Eye contact with acids or alkalis (table 3) requires emergency evaluation and treatment to prevent permanent vision loss. Alkaline substances usually cause more severe damage than acids because of the ability to saponify phospholipid membranes, which permits deeper penetration of the burn. Patients with chemical eye burns present with decreased vision, moderate to severe eye pain with photophobia, blepharospasm (inability to open the eyelids), conjunctival redness, and corneal and conjunctival burns. In severe cases of alkaline exposure, the eye may appear white, in part due to ischemia of the conjunctiva and scleral vessels (picture 3). Thorough emergency irrigation with sterile normal saline or water is mandatory, and emergency ophthalmology consultation is indicated. The management of chemical eye burns is discussed in greater detail separately. (See "Topical chemical burns: Initial evaluation and management", section on 'Patient with eye exposure'.)

Conjunctivitis — Acute vision loss occurs rarely in children with infectious conjunctivitis, except for newborns with gonococcal keratoconjunctivitis. However, differentiating conjunctivitis from keratitis (corneal inflammation), especially in patients who wear contacts or are suspected of Herpes simplex virus infection, is a major concern. (See "Conjunctivitis" and "Gonococcal infection in the newborn", section on 'Ophthalmia neonatorum' and "The red eye: Evaluation and management", section on 'Infectious keratitis'.)

Chlamydia trachomatis is the most frequent infectious cause of vision loss in developing countries, but trachoma is a more chronic condition, characterized by primary infection in childhood and the development of blindness during adulthood caused by corneal scarring from entropion and trichiasis. (See "Trachoma".)

Keratitis — Infectious keratitis (inflammation of the cornea) is most commonly caused by bacteria (especially Staphylococcus aureus and Pseudomonas aeruginosa), Herpes simplex virus, and adenovirus (epidemic keratoconjunctivitis [EKC]).

Bacterial keratitis occurs almost exclusively in contact lens wearers and may progress to corneal ulceration with hypopyon (layering of white blood cells in the anterior chamber) within 24 hours (picture 4). The diagnostic finding in bacterial keratitis is a corneal opacity or infiltrate (typically a round white spot) in association with red eye, photophobia, and foreign body sensation. Treatment requires urgent ophthalmological referral and prompt initiation of topical bactericidal antibiotics (ideally after obtaining cultures). (See "The red eye: Evaluation and management", section on 'Bacterial keratitis'.)

Primary herpes simplex virus keratoconjunctivitis is characterized by a dendritic pattern on fluorescein staining of the cornea (picture 5). Multiple recurrences can lead to scarring and consequent vision loss. Although typically a self-limited process, duration of symptoms is reduced by topical or oral antiviral agents. Patients should be referred to an ophthalmologist within a few days for confirmation of diagnosis, ongoing vision monitoring, and possible addition of adjunctive topical glucocorticoid steroid therapy (which should only be prescribed by an ophthalmologist). (See "Herpes simplex keratitis" and "The red eye: Evaluation and management", section on 'Viral keratitis'.)

EKC or adenoviral keratitis is typically a self-limited process without sequelae. However, patients can be quite miserable during active disease because of photophobia and foreign body sensation (picture 6). Rapid testing for adenovirus infection may help differentiate EKC from other types of keratitis. Referral to an ophthalmologist within days is warranted for confirmation of the diagnosis, vision monitoring, and treatment for those patients with decline in vision caused by subepithelial corneal infiltrates.

Hyphema — Hyphema, a collection of blood in the anterior chamber of the eye, typically results from blunt trauma to the eye in children (eg, struck by tennis ball or baseball). In addition to a hyphema, small objects (eg, paper clips, nails) tend to cause corneal abrasions or globe perforation, and large, hard objects (eg, fist, baseballs) often result in orbital fractures (picture 7A-B and picture 8). Spontaneous hyphema occurs rarely in children.

A large hyphema may be noticeable when looking at the patient. In most instances, simply shining a tangential light into the anterior chamber reveals the characteristic crescentic accumulation of blood. Diagnosis of a small, or microhyphema, requires the use of a slit lamp. The size of the hyphema correlates with visual outcome (figure 3). Permanent vision loss is also associated with the development of rebleeding or acute glaucoma. Patients with sickle hemoglobinopathies or bleeding disorder are at highest risk for permanent sequelae. (See "Traumatic hyphema: Clinical features and diagnosis", section on 'Pathophysiology'.)

Patients with a grade I or greater hyphema, sickle cell disease or trait, bleeding dyscrasia, or concern for an open globe need emergent evaluation by an ophthalmologist. In otherwise healthy children with a microhyphema, discussion with an ophthalmologist is recommended to address appropriate management and to ensure timely follow-up. (See "Traumatic hyphema: Management", section on 'Ophthalmologic management'.)

Iritis — Iritis is a form of anterior uveitis that causes pain, photophobia, and sometimes vision loss. Traumatic iritis is not uncommon in children with blunt periorbital injuries. Other causes, such as rheumatologic conditions, tend to present subacutely or chronically. Slit lamp and funduscopic examination is necessary to establish the presence of uveitis. Treatment of traumatic iritis consists of cycloplegia (pharmacologic pupillary dilation), topical steroid drops (only for patients under the care of an ophthalmologist), and management of associated injuries. (See "Uveitis: Etiology, clinical manifestations, and diagnosis" and "Traumatic hyphema: Clinical features and diagnosis" and "Traumatic hyphema: Management".)

Glaucoma — Glaucoma defines a group of eye diseases that is traditionally characterized by elevated intraocular pressure (IOP) and is most prevalent in adults. Glaucoma occurs rarely in childhood and may present with a painful red eye. Children may also demonstrate photophobia, a cloudy cornea, or if under three years of age at onset, buphthalmos (an enlarged eye). Older children usually complain of visual loss. Early diagnosis and referral are crucial to ensure optimal visual outcome. Childhood glaucoma is discussed in greater detail separately. (See "Overview of glaucoma in infants and children", section on 'Classification'.)

Lens abnormality — Changes in the clarity, or positioning (ectopic lentis) of the crystalline lens may alter the focus of light onto the retina, resulting in visual disturbance. Ectopic lentis is seen in pediatric patients with familial or idiopathic ectopia lentis, homocystinuria, Marfan syndrome, and trauma (picture 9). Lens clouding (cataract) typically does not occur acutely, except in the setting of trauma. (See "Ectopia lentis (dislocated lens) in children".)

Vitreous hemorrhage — Trauma is the major cause of bleeding into the vitreous humor in children. In particular, abusive (shaking) head trauma often results in this injury. On occasion, this may appear as a dome-shaped hemorrhage that obscures the retina. Other rare causes include spontaneous retinal tear, spontaneous vitreous detachment, and retinal neovascularization (as in poorly controlled diabetes) (picture 10). (See "Child abuse: Eye findings in children with abusive head trauma (AHT)".)

On physical examination, the reduction in vision is directly proportional to the amount of blood in the vitreous. If the hemorrhage is dense enough, there may be a decreased red reflex (the reddish orange reflection of light off of the retina when examining the eye with an ophthalmoscope), or the retina may not be visible with ophthalmoscopy.

Endophthalmitis — Endophthalmitis (internal eye infection) may complicate open globe injuries, eye surgery, and keratitis and is typically caused by surface pathogens. Patients present with decreased vision, pain, and red eye. A hypopyon (layering of white blood cells in the anterior chamber) may be detected (picture 11). Emergency ophthalmologic consultation for possible intravitreal treatment and/or vitrectomy is indicated. Intravenous antibiotics alone are insufficient to eradicate the infection. (See "Bacterial endophthalmitis", section on 'Treatment'.)

Retina

●Retinal detachment or hemorrhage – Retinal hemorrhage or detachment is highly suggestive of child abuse when it occurs in young, healthy infants and children without a history of serious trauma, for example, an acceleration-deceleration mechanism, such as a high-speed motor vehicle collision (see "Child abuse: Eye findings in children with abusive head trauma (AHT)", section on 'Retinal hemorrhages'). Retinal injury rarely occurs spontaneously (eg, as a late complication of retinopathy of prematurity) or in the setting of unintentional trauma. Retinal detachment can complicate Stickler syndrome, a rare inherited disorder of collagen synthesis [1,2]. Verbal patients may describe sudden onset of new floaters, black dots, or curtains in their vision, often accompanied by flashes of light (photopsias). In its early stages, a detachment may present as a persistent missing portion of the monocular visual field. Once the macula (central retina) has become involved, visual acuity will be severely compromised.

Retinal detachment is not painful, and does not cause a red eye. There may be a dulling of the red reflex, and ophthalmoscopic examination may reveal the retina to be elevated with folds (picture 12). If the detachment is extensive, there may be a relative afferent pupillary defect (figure 4). (See "Retinal detachment".)

●Central retinal artery occlusion – Although rare in pediatrics, central retinal artery occlusion (CRAO) presents with sudden, painless, severe, central and/or paracentral monocular vision loss. In children and adolescents, retinal arterial occlusion is associated with sickle cell disease, congenital heart disease with right to left shunting, hypercoagulable states, thrombotic disorders, IV drug abuse, migraine, ocular trauma, pregnancy, oral contraceptives, and vasculitis (eg, immunoglobulin A vasculitis [Henoch-Schönlein purpura], systemic lupus erythematosus) [3].

Within minutes to hours of the occlusion, the only abnormality noted on ophthalmoscopy may be vascular narrowing. An embolus is visible in about 20 percent of patients with CRAO. After several hours, the inner layer of the retina becomes ischemic, turning milky white, except in the fovea which appears as a cherry-red spot (picture 13) when compared with the unaffected eye (picture 14). An afferent pupillary defect is typically present (figure 4). Emergency ophthalmologic intervention to restore retinal circulation must occur as soon as possible to recover central vision. (See "Central and branch retinal artery occlusion", section on 'Acute treatment'.)

●Central retinal vein occlusion – In children, the very rare occurrence of occlusion or thrombosis of the central retinal vein is associated with hyperviscosity, coagulopathy, and migraine. The cause of central retinal vein occlusion (CRVO) is often unknown. Thrombosis of the central retinal vein results in venous stasis, leading to disc swelling, diffuse nerve fiber layer and preretinal hemorrhage, and cotton wool spots that create a dramatic appearance, often called "the blood and thunder" fundus (picture 15). (See "Retinal vein occlusion: Epidemiology, clinical manifestations, and diagnosis", section on 'Findings on eye examination'.)

In contrast to CRAO, the onset is typically subacute although vision loss may still be severe. When venous stasis is severe, infarction may occur due to slowed retinal blood flow on the arterial side. In this setting, a relative afferent pupillary defect is often present (figure 4). (See "Retinal vein occlusion: Epidemiology, clinical manifestations, and diagnosis", section on 'Findings on eye examination'.)

Little data exists concerning the treatment of CRVO in children. The treatment of central retinal vein occlusion in adults is discussed in detail separately. (See "Retinal vein occlusion: Treatment".)

●Retinal tumors – Retinoblastoma, the most common intraocular malignancy of childhood, exists in sporadic and heritable forms. Children with retinoblastoma frequently (but not always) present with leukocoria (an abnormal, white light reflex), also known as the amaurotic cat's eye reflex (picture 16). Prompt referral to ophthalmology and other pediatric specialists (eg, pediatric oncology) is necessary to optimize visual outcome and survival. (See "Retinoblastoma: Clinical presentation, evaluation, and diagnosis", section on 'Clinical presentation'.)

While vascular malformations, such as hemangiomas, are common in children, hemangioma of the retina is quite rare. It may present with an acute loss of monocular vision due to hemorrhage. Sometimes the blood must be completely resorbed before the tortuous vessels of the hemangioma can be fully identified [4].

Neurovisual pathway

●Orbital infections – Orbital cellulitis is localized posterior to the orbital septum (postseptal cellulitis,) and involves infection of the fat and muscle contained within the bony orbit. Sinusitis is the most common risk factor for orbital cellulitis because of the proximity of the ethmoid sinus to the orbit and the thin layer of bone (lamina papyracea) that separates the two spaces. (See "Orbital cellulitis" and "Preseptal cellulitis", section on 'Anatomy' and "Orbital cellulitis", section on 'Anatomy'.)

Clinical manifestations of orbital cellulitis include fever, proptosis (protrusion of the globe), a "down and out" position of the globe, limitation of eye movements, double vision, and/or vision loss due to orbital apex involvement. The diagnosis of orbital cellulitis is made by a combination of physical examination, including visual acuity and ocular motility assessment, and radiologic assessment with computed tomography of the orbit. Orbital infection warrants timely consultation with an ophthalmologist and otorhinolaryngologist (ear, nose, and throat surgeon). (See "Orbital cellulitis".)

Complications of orbital cellulitis may develop rapidly and include localized abscesses of the subperiosteal bone and orbit, abscess extension to the orbital apex with visual loss (orbital apex syndrome), and/or extension intracranially via the valveless venous system resulting in intracranial abscess, meningitis, or cavernous sinus thrombosis. (See "Orbital cellulitis", section on 'Clinical manifestations' and "Acute bacterial rhinosinusitis in children: Clinical features and diagnosis", section on 'Complications'.)

The orbital apex syndrome refers to compression of the optic nerve with vision loss by a mass lesion in the orbital apex, the anatomic region containing the superior orbital fissure and optic canal. There may be no external signs of orbital infection other than vision loss. Sphenoid sinusitis, in particular, may be complicated by the orbital apex syndrome, due to the anatomic proximity of the sphenoid sinus to the optic canal [5,6]. Sphenoid sinusitis is easily misdiagnosed, because it can present with headache alone and without upper respiratory symptoms. Rarely, sphenoid sinus mucocele can exert pressure on the optic nerve with resultant vision loss [7].

●Cavernous sinus thrombosis – Septic thrombosis of the cavernous sinuses can lead to vision loss due to vascular compression of the optic nerve or thrombosis of ophthalmic vessels (figure 5). The septic emboli initiating the thrombosis most commonly originate in infections involving the sinuses, face, ears, or oral cavity [8-10]. (See "Cerebral venous thrombosis: Etiology, clinical features, and diagnosis".)

●Orbital neoplasms – Neuroblastoma may metastasize to the orbital tissues, sometimes resulting in proptosis or periorbital ecchymosis and, rarely, can present with blindness [11-15]. Visual loss during treatment has also been described and may represent a complication of therapy or progression of disease [13]. (See "Clinical presentation, diagnosis, and staging evaluation of neuroblastoma".)

Rhabdomyosarcoma most often presents in the head and neck region, and loss of vision may be the first sign of such a tumor. Because rhabdomyosarcoma tends to be a slow-growing tumor, vision typically declines gradually [16]. (See "Rhabdomyosarcoma in childhood and adolescence: Clinical presentation, diagnostic evaluation, and staging".)

Rarely, acute lymphoblastic leukemia and lymphoma can present with orbital involvement and orbital infiltration [17,18].

●Idiopathic intracranial hypertension (IIH) – IIH (previously called pseudotumor cerebri) is characterized by increased intracranial pressure with compression of the optic nerve occurring in the absence of a space-occupying lesion or central nervous system infection. Its etiology is usually idiopathic, but associations with obesity and medications (eg, desmopressin, isotretinoin, steroids, tetracycline, vitamin A) have been reported. (See "Idiopathic intracranial hypertension (pseudotumor cerebri): Epidemiology and pathogenesis".)

Common findings of IIH include headache, transient visual defects, and papilledema (picture 17A-B). Untreated IIH can result in permanent vision loss due to increased pressure on the optic nerve, typically affecting peripheral vision. However, complete visual loss can happen at any time during the course of the illness. Treatment is aimed at rapid reduction of pressure on the optic nerve. (See "Idiopathic intracranial hypertension (pseudotumor cerebri): Clinical features and diagnosis" and "Idiopathic intracranial hypertension (pseudotumor cerebri): Prognosis and treatment".)

●Optic neuritis – Optic neuritis (retrobulbar neuritis, papillitis) is characterized by inflammation, demyelinization, or degeneration of the optic nerve in association with significant vision loss that is often monocular (but can be binocular). Other findings include eye pain and photopsias (brief flashes of light), especially with movement of the eye, and papillitis (picture 18). Outcome varies, depending on the etiology. (See "Optic neuritis: Pathophysiology, clinical features, and diagnosis" and "Optic neuropathies".)

When it occurs, optic neuritis in children frequently follows a viral or bacterial infection, but quite often, there is no known etiology. Lyme disease, as an example, has been implicated in causing optic neuritis and blindness. With Lyme disease, loss of vision may result from inflammation of the optic nerve itself or from elevated intracranial pressure secondary to meningitis. (See "Optic neuropathies" and "Lyme disease: Clinical manifestations in children".)

Optic neuritis may be the presenting sign of multiple sclerosis in children. Magnetic resonance imaging typically shows additional white matter lesions in these patients. (See "Pathogenesis, clinical features, and diagnosis of pediatric multiple sclerosis".)

●Optic nerve ischemia – Ischemic optic neuropathy has been reported after spinal surgery [19].

●Optic pathway glioma and other tumors – Optic glioma is the most common tumor of the optic nerve in childhood and is associated with neurofibromatosis type 1 (NF-1). These tumors typically represent pilocytic astrocytomas and grow slowly. However, significant visual field deficits are a potential indication for chemotherapy. Rarely, more rapid growth or hemorrhage can occur, compromising vision significantly. Optic pathway gliomas also arise in the optic chiasm, hypothalamus, or anterior third ventricle. (See "Optic pathway glioma".)

Acute lymphoblastic leukemia (ALL) may infiltrate the optic nerve and eye in children, causing a loss of vision [17,20,21]. Like the testicle, the eye is an important "sanctuary" site for leukemic cells where leukemia may recur after therapy [17,20].

Rarely, non-Hodgkin's lymphoma has presented with acute vision loss due to direct optic nerve compression by tumor mass, or from ischemia [16,18,22]. Third, fourth, and sixth nerve palsies may also occur.

●Optic nerve avulsion – Optic nerve avulsion from penetrating or blunt trauma is a rare cause of blindness. Any sharp object penetrating the globe can cause optic nerve avulsion [23]. Optic nerve avulsion may occur even in cases where the globe appears intact and likely results from a forced rotational movement or a rapid rise in intraocular pressure.

●Optic chiasm pathology – Involvement of the chiasm is suggested by visual loss of any type associated with pituitary dysfunction, or by a bitemporal hemianopia (figure 2).

Compressive chiasmal lesions typically cause gradual decline in vision, as they impinge upon the chiasm, optic nerve, or optic tract. Peripheral vision loss is often asymptomatic until visual acuity is compromised. Thus, most visual complaints are of gradual blurring or dimming of vision. Sudden chiasmal vision loss is less common, and implies a rapidly expanding mass, or an infectious, vascular, or inflammatory cause. Craniopharyngioma is the most common tumor involving the optic chiasm in children. (See "Craniopharyngioma".)

●Retro-chiasm pathology – Brain lesions in the region of the optic tract, the lateral geniculate body, the optic radiations, or the visual cortex produce a loss of vision on one side of both visual fields (figure 2). The visual field defect is relatively symmetric, and respects the vertical midline. No other eye abnormalities are seen. The most common causes are stroke or hemorrhage into a brain tumor.

Meningitis or occipital cerebral abscess can also result in blindness, due to various mechanisms, especially cortical damage [24,25]. Extensive bilateral damage to the cerebral visual pathways (eg, following prolonged hypoxia or shock) may result in complete loss of vision (cortical blindness). Patients with cortical blindness due to carbon monoxide poisoning have a history of exposure with elevated carboxyhemoglobin or abnormal measured co-oximetry values. Rarely, dialysis patients with profound uremia experience cortical blindness that resolves with dialysis.

Reversible posterior leukoencephalopathy (RPLS), also called posterior reversible encephalopathy syndrome (PRES), is a clinical syndrome of headache, confusion or decreased level of consciousness, visual disturbances, and seizures that is typically associated with characteristic neuroimaging findings of posterior cerebral white matter edema. Visual changes include visual auras, visual hallucinations, visual neglect, hemianopia, and cortical blindness. The patient may not appreciate cortical blindness and may deny it (Anton syndrome). RPLS has become an increasingly recognized disorder. In the appropriate clinical setting, such as severe hypertension, preeclampsia, renal disease, or cytotoxic or immunosuppressive therapy, clinicians should recognize this neurologic syndrome and order brain magnetic resonance imaging (MRI) to support the diagnosis. Diffusion-weighted imaging (DWI), if available, adds considerable diagnostic and sometimes even prognostic information. (See "Reversible posterior leukoencephalopathy syndrome".)

Other conditions

Functional visual loss — Patients describing visual loss without an organic basis are said to have "functional" visual loss. Patients who are purposely feigning blindness are malingerers, whereas those who truly perceive blindness have a conversion disorder. The visual loss may be monocular or binocular, total or sub-total. Malingerers have been known to pharmacologically alter pupillary function. (See "Somatic symptom disorder: Assessment and diagnosis", section on 'Terminology and DSM-5'.)

The typical child with functional visual loss is a female teenager [26]. These patients walk more carefully through the waiting area or examination room and are not likely to bump into objects or hurt themselves [27]. While older patients with hysterical blindness are recognizable by "la belle indifference," a seeming lack of concern with their sudden blindness, younger children may express great worry about their symptoms [28]. The ocular examination is entirely normal. The ability to elicit nystagmus with an optokinetic drum (rotating drum with alternating vertical white and black stripes) is one method to prove the presence of vision to skeptical parents. Management generally includes referral for psychotherapy [26,28].

Conversion disorders are well described in the pediatric population and are thought to be a result of involuntary somatization of unresolved psychological issues [27,28]. Conversion reactions frequently stem from conflicts surrounding school changes, new social settings, or family stress [28,29]. Psychiatric comorbidity (eg, depression, posttraumatic stress disorder) is common.

Toxins — Untreated methanol overdose results in specific ocular toxicity characterized by destruction of optic nerve and pigmented retinal epithelial cells. Visual disturbances are caused by the formate metabolite and may occur up to 72 hours after ingestion. Patients describe several visual disturbances including blind spots, snow field vision, and loss of color vision. An afferent pupillary defect (figure 4) is an ominous and late sign of advanced methanol poisoning. Eye examination in methanol poisoning may also reveal mydriasis, a retinal sheen due to retinal edema, and hyperemia of the optic disc. (See "Methanol and ethylene glycol poisoning: Pharmacology, clinical manifestations, and diagnosis".)

Any ingestion that causes significant occipital cerebral ischemia or hypoxia may cause cortical blindness. Mechanisms include interference with cerebral oxygen delivery (eg, carbon monoxide), production of shock (eg, nifedipine), local cerebral vasospasm (eg, amphetamines), and direct neurotoxicity (eg, cisplatin) [30].

Other primary ocular tumors — While uveal melanoma is the most common primary intraocular malignancy in adults, only 1 to 2 percent of cases present in patients younger than 20 years old [31]. (See "Initial management of uveal and conjunctival melanomas".)

Astrocytic hamartoma (which is associated with tuberous sclerosis), combined retinal hamartoma (associated with neurofibromatosis), juvenile xanthogranuloma, medulloepithelioma, and retinal hemangioblastoma (in von Hippel-Lindau disease) are some other ocular tumors that can rarely result in vision loss in children [31,32]. (See "Neurofibromatosis type 1 (NF1): Pathogenesis, clinical features, and diagnosis", section on 'Clinical manifestations' and "Tuberous sclerosis complex: Clinical features", section on 'Ophthalmic manifestations'.)

Transient vision loss

●Migraine – Migraine is the most common cause of transient bilateral vision loss (TBVL) in adolescents and young adults. Headache and positive visual phenomena, such as scintillations, usually occur in these patients. The classic migraine aura typically lasts 20 to 30 minutes, rarely as long as an hour, and has a characteristic build-up, or evolution, a feature lacking in other causes of TBVL (eg, seizure). The mechanism of visual loss in migraine is thought to be neuronal depression after a period of cortical excitation ("spreading depression of Leao") as well as transient cerebral vasospasm. (See "Pathophysiology, clinical manifestations, and diagnosis of migraine in adults", section on 'Migraine aura' and "Pathophysiology, clinical manifestations, and diagnosis of migraine in adults", section on 'Pathophysiology'.)

In young children, migraines may be associated with confusion, vomiting, visual changes, and hemiplegia that may follow mild head trauma and typically resolve within 24 hours. A strong family or personal history of migraines is often present. (See "Types of migraine and related syndromes in children".)

Rarely, ocular migraine may cause monocular vision loss or the perception of bright light (photopsia) or scintillations in one eye only, followed within one hour by a migrainous headache. The neurologic symptoms are fully reversible. The headache is typically ipsilateral and periorbital. Visual symptoms may occur without headache. Vision usually recovers in this condition, although permanent visual loss may occur. (See "Types of migraine and related syndromes in children", section on 'Retinal migraine'.)

●Head trauma – Transient cortical defects, such as cortical blindness and acute confusional states, have been reported in association with minor head injury. These deficits are thought to be secondary to vascular hyperreactivity and may be trauma-induced (eg, occipital concussion) or migraine-equivalent phenomena. A typical case is a child with head trauma followed by loss of consciousness who awakens blind, but whose blindness resolves completely within hours of the event. If neurologic symptoms persist, a full evaluation for brain injury must ensue. Permanent vision loss can result from intracranial injury [33]. (See "Minor blunt head trauma in infants and young children (<2 years): Clinical features and evaluation", section on 'Clinical features' and "Minor blunt head trauma in children (≥2 years): Clinical features and evaluation", section on 'Clinical features'.)

●Seizure – Occipital epilepsy of childhood, sometimes referred to as Gastaut-type, has a mean age of presentation of eight to nine years (range 3 to 16 years). Seizures are typically brief (1 to 10 minutes) and often include visual symptoms, such as visual hallucinations or colored circles. Blindness is rare. Hemiclonic activity, automatisms, migraine-like headache, and versive movements may also occur, and seizures may secondarily generalize. An abnormal electroencephalogram (EEG) confirms the diagnosis. Antiseizure medication treatment is more often prescribed than in other partial epilepsy syndromes since the duration of epilepsy is longer and seizures can be frequent. (See "Self-limited focal epilepsies of childhood", section on 'Childhood occipital visual epilepsy (COVE)'.)

HISTORY AND PHYSICAL FINDINGS

History — Key historical information includes:

●Timing – Ascertaining the exact moment when vision was lost can be helpful diagnostically, but difficult to pinpoint historically. Because children typically compensate well, especially when only one eye is affected, they may not realize that sight is deteriorating until seriously impaired [16,34]. If the normal eye is inadvertently covered, a longstanding or gradual loss of vision in the other eye may be mistaken for acute loss. School records documenting prior visual acuity may be useful.

●Binocular versus monocular vision loss – True binocular vision loss in the absence of ophthalmoscopic findings suggests a retrochiasmal visual pathway disorder or bilateral optic neuritis. (See "Optic neuritis: Pathophysiology, clinical features, and diagnosis".)

●Trauma – Mild trauma can cause corneal abrasion or uveitis; more severe trauma can cause hyphema, vitreous hemorrhage, traumatic cataract, retinal detachment, or traumatic optic neuropathy. Trauma with a sharp or blunt object may produce an open globe. Head trauma may cause a transient loss of vision due to occipital concussion. In infants and small children, abusive (shaking) head injury is an all too frequent cause of retinal and vitreous hemorrhages with or without papilledema. (See "Child abuse: Eye findings in children with abusive head trauma (AHT)".)

●Pain – The quality of the eye pain may assist in diagnosis:

•Keratitis – Sharp superficial eye pain

•Acute glaucoma – Deep brow ache with nausea and vomiting

•Endophthalmitis – Deep boring pain

•Optic neuritis or orbital infection – Pain worse with eye movement

●Headache – Patients with migrainous vision loss or idiopathic intracranial hypertension typically have an associated headache.

●Photophobia – Patients with media disorders, including keratitis, traumatic hyphema, and iritis typically have intense photophobia.

●Fever – Fever in conjunction with proptosis and pain on eye motion suggests an orbital infection.

●Contact lens wear – Contact lens wear is a risk factor for microbial keratitis, especially with soft lenses and when lenses are used improperly (poor hygiene, overnight wear, contaminated solutions). (See "The red eye: Evaluation and management", section on 'Bacterial keratitis'.)

●Photopsias – Patients with optic neuritis often describe photopsias (flashes of light) with pain on eye movement. Painless photopsias occur in patients with retinal detachment.

●Recent treatment with eye drops – Over-treatment of both conjunctivitis and keratitis with topical medications (particularly topical anesthetics) can result in ulcers, which can threaten sight [35].

●Associated symptoms – Neurologic deficits can accompany a migraine headache, seizure, stroke (homonymous defect), or multiple sclerosis (optic neuritis). Nausea and vomiting may accompany severely elevated intraocular pressure and intraocular trauma (eg, traumatic hyphema). Rhinorrhea is common when tearing is present. Some patients with monocular or binocular vision loss complain of a vague sense of disorientation or difficulty with balance and depth perception.

●Past medical history – Conditions that predispose to specific types of vision loss include sickle cell disease (stroke, central retinal artery occlusion, glaucoma in the setting of traumatic hyphema), thrombotic disorders (cavernous sinus thrombosis, central retinal vein thrombosis), migraine (transient vision loss), partial seizures (occipital epilepsy of childhood), and psychiatric illness (conversion disorder).

Physical examination — Patients with suspected globe rupture or laceration should not undergo lid retraction or other procedures that may apply pressure to the eye. In addition, topical drops (eg, fluorescein, anesthetic drops) should not be applied except by an ophthalmologist. The examination of a patient with eye injuries is discussed in detail separately. (See "Approach to diagnosis and initial treatment of eye injuries in the emergency department", section on 'Sequential eye examination'.)

Reduced ambient light and parental presence facilitate cooperation in the child. Once an open globe is excluded, topical analgesia may be provided, if helpful, for pain and photophobia.

The clinician should perform a complete ocular examination, starting away from the patient and evaluating each of the anatomical components of vision in turn. Potentially frightening or painful procedures (eg, bright illumination of the injured eye, funduscopic examination, lid retraction) should be performed later in the evaluation [36]. Key aspects of the examination include (see "Approach to diagnosis and initial treatment of eye injuries in the emergency department", section on 'Sequential eye examination'):

●Patient level of consciousness and ability to cooperate with the examination

●Visual acuity of each eye independently

●Inspection of the orbit, eyelid, and surrounding structures

●Extraocular movement

●Confrontational visual fields

●Pupillary appearance and response to light (including the swinging flashlight test (figure 4))

●Evaluation of anterior chamber depth and presence of visible hyphema using a penlight

●Presence of a red reflex

●Direct funduscopic examination

●Eversion of the eyelids

●Slit lamp examination of the eye (in the older patient and by experienced clinicians)

In children younger than two to three years of age, visual behavior (table 4) rather than visual acuity is assessed. The goal is to determine whether visual behavior is normal for age and whether vision is equal between the two eyes. Visual behavior can be tested in all children. Even very young infants demonstrate visual fixation if an appropriate target (eg, the human face) is used. (See "Vision screening and assessment in infants and children".)

In addition to monocular or binocular diminished visual acuity, key abnormal findings include:

●Periorbital swelling (eye trauma, orbital infection).

●Signs of an open globe (eg, eccentric or peaked pupil, obvious laceration, protruding intraocular foreign body, or evidence of extrusion of ocular contents). If present, a stiff, protective shield (that does not put pressure on the eyeball) should be applied and an ophthalmologist should be consulted immediately. (See "Open globe injuries: Emergency evaluation and initial management", section on 'Initial emergency assessment and treatment'.)

●Proptosis (orbital infection and/or mass).

●Conjunctival injection (conjunctivitis, keratitis, corneal injury, uveitis/iritis, endophthalmitis, or glaucoma).

●Blood (hyphema) or pus (hypopyon) in the anterior chamber.

●Pain on extraocular movement (orbital infection, optic neuritis).

●Homonymous visual field abnormalities (retrochiasmal disorders).

●Afferent pupillary defect (unilateral optic nerve pathology) (figure 4); to compare pupillary reflexes, the clinician should examine the pupils from such a distance that both eyes are visible at once [37].

●Abnormal red reflex; a dull reflex indicates obstruction anterior to the retina, and can be caused by tumor or hemorrhage [38]. A white reflex (leukocoria) is worrisome for cataract, Coats disease, intraocular tumor, or retinal detachment (picture 16) [16].

●Abnormal funduscopic examination such as pallor (central retinal artery occlusion), abnormal vessels, retinal hemorrhage (abusive head trauma in young infants), papilledema (idiopathic intracranial hypertension, abusive head trauma, intracranial mass lesions), or papillitis (optic neuritis).

●Evidence of conversion disorder; patients with hysterical blindness carefully avoid falling or bumping into things. Optokinetic reflex (involuntary horizontal nystagmus when looking at a rotating drum with alternating vertical white and black stripes) is intact. Additionally, a mirror placed in front of the patient's eyes can be tilted in different directions and a seeing patient's eyes will move [27].

●Fluorescein staining identifies corneal and conjunctival defects (eg, corneal abrasion or keratitis), but is contraindicated in the patient with an open globe.

●Slit lamp examination is best for identifying microhyphema, hypopyon, iritis, and lens abnormalities. (See "Slit lamp examination".)

●When a complete ocular examination in a truly blind patient is normal, cortical blindness is the presumptive diagnosis [30].

●Tonometry (intraocular pressure measurement) may be performed by an appropriately trained emergency physician or by an ophthalmologist. Ophthalmology consultation is generally needed to obtain indirect funduscopy, formal visual field testing, or visual evoked responses.

Diagnostic studies — Specific laboratory tests (eg, complete blood count [CBC], hemoglobin electrophoresis, coagulation studies, blood culture, Lyme titers, toxicology screen, lumbar puncture) and diagnostic tests (eg, head computed tomography [CT], magnetic resonance imaging [MRI], electroencephalography [EEG]) should be obtained based on clinical suspicion.

High resolution, thin-slice, orbital CT with coronal images is preferred for evaluation of orbital trauma, bony injuries, orbital cellulitis, and intraocular foreign bodies. MRI is best for identifying optic nerve tumors, optic neuritis, and other soft tissue ocular anomalies [39-42]. MRI should not be performed in patients with metallic intraocular foreign bodies. Plain radiographs or orbital CT should be obtained before MRI to exclude this diagnosis.

APPROACH — The child with acute vision loss must undergo a rapid evaluation to determine the most likely etiology (algorithm 1A-B). Life-threatening causes include intracranial injury, intracranial mass lesion with impingement of the neurovisual pathway, malignant eye tumors, methanol poisoning, and carbon monoxide poisoning.

Patients with intraocular trauma, chemical burns, orbital infection, central retinal artery occlusion, and endophthalmitis warrant emergency ophthalmologic consultation in order to provide the best chance for preservation of vision.

Monocular vision loss — Traumatic injury is an important cause of monocular vision loss in children (algorithm 1A). Initial assessment should identify signs of a ruptured or lacerated globe. If present, the patient should have an eye shield placed and emergency ophthalmologic consultation obtained. Patients without concern for an open globe require a complete eye examination to evaluate for serious corneal injury (eg, chemical burn) or traumatic hyphema. Damage to more posterior structures (eg, lens, retina, vitreous, optic nerve) may coexist with a traumatic hyphema. (See 'Chemical burn' above and 'Open globe' above and 'Hyphema' above.)

Careful eye examination helps differentiate the causes of nontraumatic monocular vision loss:

●Patients with nontraumatic, painful vision loss and a red eye warrant measurement of intraocular pressure (IOP). Increased IOP identifies glaucoma and may occur in some patients with uveitis and endophthalmitis. Individuals with normal IOP may have keratitis, uveitis, or endophthalmitis. (See 'Glaucoma' above and 'Conjunctivitis' above and 'Keratitis' above and 'Iritis' above.)

●Pain on extraocular movement without conjunctival redness may indicate orbital infection, cavernous sinus thrombosis, or optic neuritis.

●Leukocoria (abnormal white reflex) is seen in patients with an intraocular tumor or cataract. (See 'Retina' above and 'Lens abnormality' above.)

●Abnormal funduscopic examination may provide clues to the diagnosis for vitreous hemorrhage, central retinal artery occlusion (pale optic disc and cherry red spot), central retinal vein occlusion (blood and thunder fundus), retinal hemorrhage or detachment, optic neuritis (disc swelling), or idiopathic intracranial hypertension or central nervous system mass lesions (papilledema). (See 'Retina' above and 'Vitreous hemorrhage' above and 'Neurovisual pathway' above.)

●Patients with monocular vision loss, a normal eye examination, and preserved optokinetic reflex have functional blindness (conversion disorder). Patients with ocular migraine may demonstrate transient monocular vision loss, often with unilateral headache. Acute optic nerve impingement caused by a rapidly expanding CNS lesion or a tumor along the path of the optic nerve rarely causes monocular vision loss without abnormality on eye examination.

Binocular vision loss — Trauma remains an important consideration in the evaluation of binocular vision loss (algorithm 1B). Bilateral eye trauma may cause total loss of vision. Etiologies are the same as for monocular vision loss (algorithm 1A). Patients who have vision loss in conjunction with head trauma warrant neuroimaging to differentiate among intracranial injury with increased intracranial pressure, occipital intracranial injury, and occipital concussion.

Patients with conversion disorder have a normal eye examination, intact optokinetic nystagmus, and reaction to visual threat. Transient vision loss with a history of a recent seizure and interictal occipital abnormalities on EEG indicates occipital epilepsy of childhood. Transient vision loss characterized by visual scintillations with a progressive build up followed by headache is seen in patients with migraine.

Papilledema on funduscopic examination indicates increased intracranial pressure (ICP) and is seen in patients with idiopathic intracranial hypertension or central nervous system mass lesion. Circumferential narrowing of peripheral vision suggests diffusely increased ICP without interruption of the neurovisual pathway. Bilateral visual field deficits that respect the vertical midline (eg, homonymous hemianopia) identify tumors with disruption of the neurovisual pathway at or behind the optic chiasm.

Vision loss due to methanol ingestion is characterized by an afferent pupillary defect and may include findings of dilated pupils, a retinal sheen due to retinal edema, and hyperemia of the optic disk. (See "Methanol and ethylene glycol poisoning: Pharmacology, clinical manifestations, and diagnosis", section on 'Clinical features of overdose'.)

Any central nervous system process that results in bilateral occipital lobe hypoxia or ischemia can cause cortical blindness. Patients with cortical blindness due to carbon monoxide poisoning have a history of exposure with elevated carboxyhemoglobin or abnormal measured cooximetry values around the time of exposure. Rarely, dialysis patients with profound uremia experience cortical blindness that resolves with dialysis.

SUMMARY

●Etiology – Acute vision loss in children is frightening, not only for the patient and family, but also for the clinician. Blindness, especially if bilateral and permanent, represents a serious loss of function. Alterations in function of any of the structures along the visual pathway may cause vision loss. Pathology can be broadly divided into three major anatomic categories (table 1):

•Media problems – Disorders of the cornea, anterior chamber, lens, vitreous, and uvea (figure 1) (see 'Visual media' above)

•Retinal problems – Vascular occlusion, retinal detachment, and retinal tumors (see 'Retina' above)

•Neurovisual pathway problems – Optic nerve, chiasmal, and retrochiasmal pathology (figure 2) (see 'Neurovisual pathway' above)

●Diagnostic approach – The diagnostic approach to monocular and binocular vision loss is summarized in the algorithms (algorithm 1A and algorithm 1B). Rapid determination of a trauma history, evaluation for an open globe (table 2), and early recognition and irrigation of ocular chemical burns to the eye are essential aspects of initial treatment. (See "Open globe injuries: Emergency evaluation and initial management" and "Topical chemical burns: Initial evaluation and management", section on 'Patient with eye exposure'.)

Life-threatening causes include intracranial injury, intracranial mass lesion with impingement of the neurovisual pathway, malignant eye tumors, methanol poisoning, and carbon monoxide poisoning. (See 'Approach' above.)

Patients with signs of intraocular trauma, chemical burns, orbital infection, central retinal artery occlusion, or endophthalmitis warrant emergency ophthalmologic consultation to provide the best chance for preservation of vision. (See 'History and physical findings' above and 'Approach' above.)