Sudden Vision Loss
A broad view and summary of a scary, sudden, and seemingly complex disorder.
An Approach to Acute Vision Loss
Acute vision loss can be very distressing to both patients and physicians and extremely important to diagnose in a timely manner. There are many different causes of acute vision loss which can occur anywhere along the visual tract, from the cornea to the occipital lobe . Acute vision loss may be benign and reversible, but it may also represent a more malignant, irreversible process. Prompt diagnosis is necessary to treat and potentially save the patient’s vision and/or life.
As with any new presenting symptom, the first step is to obtain a thorough history and physical. Acute vision loss can be caused by many different etiologies including ocular, vascular, and neurological pathologies. A detailed medical history may help determine whether one of these categories of pathology should be considered.
Some risk factors that might make one think about a primary ocular pathology include contact lens use, severe myopia, and recent eye surgery or trauma. On the other hand, cardiovascular risk factors such as diabetes, hypertension, and hyperlipidemia may increase the risk of a vascular etiology such as retinal artery or vein occlusion, cardiac emboli, carotid disease or vertebrobasilar occlusive disease.
Hematologic disorders including sickle cell anemia, Waldenstrommacroglobulinemia, or multiple myeloma can lead to a hyperviscosity syndrome, and may also indicate a vascular etiology . A personal history of multiple sclerosis should prompt an assessment of the optic nerve since optic neuritis occurs at some point in about 50 percent of patients with multiple sclerosis .
Methanol toxicity which can present as blurred “snowfield” like visual changes, or may manifest as a dense centrocecal scotoma (Complete or partial central vision loss in a horizontal oval distribution extending between the point of fixation and the blindspot), should be considered in patients with a history of drug ingestion, fire breathing using methanol, or consumption of home distilled spirits. If diagnosed early, methanol toxicity can be treated by inhibiting the metabolism of methanol with fomepizole and preventing permanent vision loss from optic atrophy .
A history of transient ischemic attack or stroke may point towards a neurologic etiology.
Many systemic medications are associated with ocular side effects, and the patient’s medication list should be reviewed. Somemedicationsassociated with acute vision loss include anticholinergics (which can present as loss of accommodation or angle closure glaucoma), sildenafil (ischemic optic neuropathy), sulfonamides (myopia), and topiramate (acute angle closure glaucoma). Most of these medications will produce visual symptoms gradually when prescribed in high doses and/or with prolonged use (except for those that induce acute angle closure glaucoma). Some examples of anticholinergic medications include atropine, benztropine mesylate, darifenacin, dicyclomine, fesoterodine, oxybutynin, tolterodine, scopolamine, and over the counter antihistamines such as diphenhydramine, brompheniramine, chlorpheniramine and meclizine.
History of Present Illness
The history of present illness may be helpful in making the correct diagnosis. Location, quality, and timing of the vision loss is important to inquire about, as well as whether the vision loss is monocular or binocular and associated with any other symptoms including ocular pain. The patient may describe blurry vision usually associated with a media-related ocular issue (the optic media includes the cornea, aqueous humor, lens, and vitreous body), a dimming of the vision indicative of avascular issue, reduction in the visual field suggestive of a retinal or neurological issue, or a showering of black dots which may be perceived by the patient in a vitreous hemorrhage. If the patient describes a floating or moving scotoma, this may also suggest a vitreous pathology.
Fixed scotomas (partial or complete vision loss in the field of vision) would indicate the pathology is in structures that are fixed relative to the globe (corneal, lenticular, retinal, optic nerve, or from neurological damage). Sudden vision blur that only lasts a few seconds may be indicative of tear film abnormalities. The tear film is a thin fluid layer covering the eye, and transient decreased vision due to an issue in the tear film may clear with blinking. Vision loss that only lasts a few seconds may also be due to papilledema, or vitreous debris. Vision loss that lasts less than 10 minutes may be associated with carotid or vertebrobasilar artery disease, cardiac emboli, or with initial symptoms of giant cell arteritis. Vision loss that lasts a couple of hours may suggest transient acute closure glaucoma, ophthalmic migraine, retinal artery/vein occlusion, retinal detachment, or optic neuritis . If the vision loss lasts over 24 hours,diagnoses include acute angle closure glaucoma, vitreous hemorrhage, retinal detachment, retinal artery occlusion, retinal vein occlusion, optic neuritis, ischemic optic neuropathy, and cerebrovascular accident . Monocular vision loss is often associated with local eye pathologies such as glaucoma, uveitis, retinitis or neurological diseases like optic neuritis or anterior ischemic optic neuropathy. Alternatively, binocular vision loss usually affects structures further back in the visual pathway including the optic chiasma, lateral geniculate body, occipital radiations, and the occipital cortex .
There are many different symptoms that are commonly associated with vision loss and can point one towards a specific diagnosis. Visual flashes of lights or floating shadows are indicative of a retinal detachment. A combination of tearing, halos around lights, nausea, and vomiting may be associated with acute angle closure glaucoma. Jaw/tongue claudication, temporal headache, proximal muscle pain and stiffness, diplopia, weight loss, and night sweats are symptoms of giant cell arteritis. Headache with vision loss may be associated with a migraine, giant cell arteritis, or pituitary apoplexy(infarction or hemorrhage of the pituitary). Presyncope symptoms may cause transient vision loss from postural hypotension. Neurologic symptoms should be reviewed for stroke or pituitary apoplexy .
The presence or absence of ocular pain can also help point one towards a specific diagnosis. Ocular pain with eye movement can be suggestive of retrobulbar optic neuritis, and if the pain is exacerbated by exercise or elevated body temperature it is known as Uhthoff’s phenomenon. Localized ocular pain may suggest a corneal pathology (ulcer or abrasion), anterior chamber inflammation, or increased intraocular pressure . Painful visual impairment can also be seen in optic neuritis, Tolosa Hunt syndrome (painful weakness of the eye muscles due to granulomatous inflammation of the cavernous sinus), orbital apex syndrome (dysfunction of the optic and cranial nerves due to a process that affects the optic canal and superior orbital fissure/orbital apex), pituitary apoplexy, and glaucoma. On the other hand, diseases of the optic tracts such as anterior ischemic optic neuropathy, the optic radiations (part of the visual tract that connects the optic tracts to the visual cortex in the occipital lobe), or the occipital cortex tend to be painless .
After a history is obtained, a thorough ocular exam should be conducted. This includes inspection, visual acuity, visual fields, tonometry, pupil examination, evaluation of extraocular movement, slit lamp examination, fluorescein application, color vision examination, red reflex examination, and fundus examination. During inspection, ptosis, proptosis, injection or chemosis should be assessed. Ptosis may indicate a neurologic process, while proptosis may signify a structural process. Injection or chemosis may indicate an ocular or retrobulbar pathology. Visual acuity and fields should be completed to confirm and specify the extent of vision loss acquired from the history. Tonometry should be performed to see if the patient has an elevated intraocular pressure which would be indicative of glaucoma. Patients with acute angle closure glaucoma present with an elevated intraocular pressure along with a cloudy/steamy cornea, a mid-dilated pupil and conjunctival injection on exam. Thus, a pupil examination, which includes evaluation of symmetry, reactivity to light, and pupillary reflex testing, is also helpful. An abnormal pupil examination may also be indicative of a neurologic process. Pupillary reaction testing should include the swinging-flashlight test to look for consensual pupillary reflexes. During the swinging-flashlight test, a light is shined into one eye and then rapidly moved to the other eye. When the light is shined into one eye, both pupils should constrict. While the light is being moved into the other eye both pupils should expand and constrict again when the light is shined into the opposite eye. If the pupils respond asymmetrically to the light stimuli, the patient would be diagnosed with a relative afferent pupillary defect (RAPD). A RAPD indicates a monocular optic nerve disease or abnormality of the retina. Exceptions include surgical, traumatic or pharmacologically altered pupils. Topical fluorescein application is used to diagnose keratitis, corneal abrasion, and corneal edema. Color vision testing helps detect optic neuropathy. A patient with optic neuropathy will perceive the color red to be either absent or duller in the affected eye. An abnormal red reflex exam indicates media opacities such as a cataract or vitreous hemorrhage or intraocular pathology such as retinal detachment or tumor [3,5].
Fundus examination may demonstrate retinal hemorrhaging and/or retinal whitening seen in retinal detachments, or cotton-wool spots which are indicative of vascular disease causing retinal arteriole obstruction and resulting damage to nerve fibers. Arteriolar narrowing or tortuosity, optic tumor, and/or venous engorgement should also be looked for. Fundus examination may also reveal optic disc swelling and pallor seen in optic neuropathy, or an increase in the cup-to-disc ratio characteristic of chronically increased intraocular pressure. The macula examination may reveal a cherry-red spot typically seen in retinal ischemia. If there are signs of giant cell arteritis which include temporal artery tenderness or induration, pale retina, or papilledema, and the patient is complaining of temporal headaches, jaw claudication, proximal myalgias or stiffness, an erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and platelet count should be ordered. If giant cell arteritis is suspected, the patient should be started on high dose steroids immediately to preserve any remaining vision. Any vision loss that already occurred is most likely irreversible. Treatment for giant cell arteritis includes methylprednisolone 1000 mg IV daily for one to three days, followed by prednisone 60 mg/day for two to four weeks [3,5].
Depending on the history and ocular examination, other aspects of the physical exam may need to be performed to narrow the differential diagnosis. These may include checking the patient’s blood pressure, blood sugar levels, (can be high or low with pituitary apoplexy), auscultating the carotid arteries for bruits, the heart for murmurs, and a careful examination of the cranial nerves. Deficits of the optic nerve, oculomotor nerve (controls movement of the eye and pupil), trochlear nerve (controls torsional movement of the eye), and the ophthalmic branch of the trigeminal (provides sensory stimuli) and abducens nerves (controls lateral movement of the eye) may indicate an orbital mass since all these nerves are located within the orbit. Alternatively, deficits in the maxillary branches of the trigeminal nerve, which runs through the cavernous sinus, and supplies sensation to the mid-third of face along with central retinal vein occlusion may indicate cavernous sinus thrombosis (a clot in the cavernous sinus which is life-threatening) .
Once the diagnosis is determined, treatment should commence immediately. In certain scenarios such as giant cell arteritis, immediate treatment can save the patient’s remaining vision. Other emergent cases that should be treated in an urgent manner include central retinal artery occlusion (CRAO), acutely elevated intraocular pressure, and pituitary apoplexy. In CRAO, it is presumed that vision loss may be reversible if blood flow is restored in approximately 100 minutes, before ganglion cell death occurs. Some interventions include attempting to lower the intraocular pressure with digital massage, paracentesis, or pharmacologic agents. Unfortunately, many of these proposed interventions have not been established in randomized trials due to the low likelihood of collecting enough subjects to do a large study . Acutely elevated intraocular pressure (IOP) due to angle-closure glaucoma should also be treated urgently since irreversible vision loss many occur within hours if the IOP remains above 40 mmHg. Initial management should include pressure-lowering eye drops such as0.5% timolol maleate (Timoptic), 1-2% Brominidine (Alphagan), and 2% pilocarpine(Isopto Carpine) one drop each, one minute apart. The order in which these drops are administered is not of importance. Note that Timoptic is contraindicated in patients with ronchial asthma, severe COPD, sinus bradycardia, second- or third-degree AV block and overt cardiac failure. Alphagan is contraindicated in patients with Raynaud’sphenomenon or Buerger’s disease, and Isopto Carpine is contraindicated in patients with inflammation of the cornea or iris or detachment of the retina. If these ocular medications cannot be given, acetazolamide administered either orally or intravenously may also help to acutely reduce intraocular pressure. Please note that acetazolamide is contraindicated if the patient is allergic to sulfa and or has sickle cell disease. Once the pressure is lowered, definitive treatment, such as laser or surgical peripheral iridotomy, should be performed . Pituitary apoplexy should always be considered whenever a patient presents with a headache associated with sudden blindness and/or ophthalmoplegia (inability to move the eye due to paralysis of the extraocular muscles). Patients with pituitary apoplexy may also present with nausea and vomiting and neck stiffness. These patients are at risk of abrupt and rapid neurological decline which can lead to depressed level of consciousness and even death if not diagnosed and treated properly. CT or MRI (preferably MRI) can reveal the diagnosis via demonstration of hemorrhage into the pituitary. Treatment includes high-dose systemic corticosteroids to avoid adrenal insufficiency and possible neurosurgical intervention. Electrolyte, glucose, and hormone levels must be evaluated as well as an emergent consultation with an endocrinologist .
In other cases, immediate treatment may not be necessary but semi-urgent referral may be needed to prevent permanent vision loss. For example, if not treated with antibiotics, microbial keratitis can lead to permanent scarring or corneal perforation. Cultures may be needed which takes some time to process. Another example includes macula-involving retinal detachment which should be surgically repaired within a week so that the patient has the best visual outcome as opposed to macular sparing retinal detachments which need to be treated more urgently . Historically, these were both treated with urgency until it was found that urgent surgical repair of macular involving retinal detachments did not yield any increased visual benefit. Unfortunately, for other etiologies such as vascular disorders, treatment is unlikely to salvage the affected eye, but it can decrease the risk of the same process occurring in the contralateral eye or of a complication caused by the same process (e.g. ischemic stroke requiring anticoagulation) . Thus, it is still important to diagnose and treat in a timely manner. Referrals to specialties other than ophthalmology may also be warranted depending on the diagnosis. For example, cardiologists should be consulted in patients with retinal artery occlusion since the most common cause of death in these patients is cardiac disease. A cardiac source such as a mural thrombus, valvular heart disease, patent foramen ovale, or arrythmia may be identified and possibly corrected. Patients who present with neurological symptoms including weakness, numbness, paresthesia, dysarthria, dysphagia, or headache should be sent to an emergency department immediately, where an emergent neurology consult can be obtained .
In conclusion, acute vision loss can present in a vast variety of ways and in many different clinical contexts. A thorough history and physical is necessary to determine the underlying cause. Other tests and referrals to different specialties may be required for diagnosis and/or treatment. Timely identification of the primary pathology is crucial to enable the clinician to treat the underlying disease process, prevent further vision loss, possibly restore full vision and to prevent any other systemic sequelae.
Hints from the PMH
Primary ocular pathology - if contact lens use, severe myopia, or recent eye surgery or trauma.
Vascular etiology (retinal artery or vein occlusion, cardiac emboli, carotid occlusive disease or vertebrobasilar disease)- if cardiovascular risk factors such as diabetes, hypertension, and hyperlipidemia are present.
Hyperviscosity syndrome and vascular etiology - from hematologic disorders including sickle cell anemia, Waldenstrom macroglobulinemia, or multiple myeloma).
Optic neuritis – if there is a history of multiplesclerosis.
Methanol toxicity -if patient has a history of drug ingestion, fire breathing, or consumption of home distilled spirits.
Neurologic pathology - if history of transient ischemic attack or stroke.
Medication related - if patient is taking an ananticholinergic (loss of accommodation or angle closure glaucoma), sildenafil (ischemic optic neuropathy), sulfonamide (myopia), or topiramate (acute angle closure glaucoma).
Hints from the HPI
Blurry vision– usually a media-related ocular issue (the optic mediai ncludes the cornea, aqueous humor, lens, and vitreous body)
Dimming of the vision –may be indicative of a vascular issue
Reduction in the visual field -suggestive of a retinal or neurologica lissue
Showering of black dots -vitreous hemorrhage
Floating, moving scotoma - may suggest a vitreous pathology
Sudden vision loss that only lasts a few seconds -may be indicative of tear film abnormalities, papilledema, optic disc drusen, or vitreous debris.
Binocular vision loss -usually affects structures further back in the visual pathway including the optic chiasma, lateral geniculate body, occipital radiations, and the occipital cortex
Flashes of lights or floating shadows- indicative of a retinal detachment
Headache- migraine, giant cell arteritis, or pituitary apoplexy (infarction or hemorrhage of the pituitary)
Ocular pain with eye movement- suggestive of retrobulbar optic neuritis (especially if exacerbated by exercise or elevated body temperature called Uhthoff’s phenomenon)
Localized ocular pain- may suggest a corneal pathology (ulcer or abrasion), anterior chamber inflammation, or increased intraocular pressure
Painful visual impairment- also be seen in optic neuritis, Tolosa Hunt Syndrome (granulomatous inflammation of the cavernous sinus), orbital apex syndrome, pituitary apoplexy, and glaucoma.
Hints from the Physical
Ptosis -may indicate a neurologic process
Proptosis -may signify a structural process
Injection or chemosis -may indicate an ocular or retrobulbar pathology
Relative afferent pupillary defect (RAPD) -indicates a monocular optic nerve disease or abnormality of the retina.
Topical fluorescein application -used to diagnose keratitis, corneal abrasion, and corneal edema.
Color vision testing -helps detect optic neuropathy.
Abnormal red reflex exam -indicates media opacities such as a cataract or vitreous hemorrhage or intraocular pathology such as retinal detachment ortumor
retinal hemorrhaging and/or retinal whitening -seen in retinal detachments
cotton-wool spots - indicative of vascular disease (e.g. ischemia from retinal arteriole obstruction and subsequent nerve fiber layer infarct)
optic disc pallor – optic neuropathy
increase in the cup-to-disc ratio -increased in chronically elevated intraocular pressure
increase in the cup-to-disc ratio -chronically increased intraocular pressure
macula cherry-red spot -retinal ischemia
deficits of the optic nerve, oculomotor nerve, trochlear nerve, and the ophthalmic branch of the trigeminal and abducens nerves -may indicate an orbital mass since all these nerves are located within the orbit.
deficits in the maxillary branches of the trigeminal nerve along with central retinal vein occlusion -may indicate cavernous sinus thrombosis.
Two Diseases You Shouldn’t Forget
Giant cell arteritis- jaw/tongue claudication, temporal headache, proximal muscle pain and stiffness, diplopia, weight loss, and night sweats
Pituitary apoplexy-headache associated with sudden blindness and/or ophthalmoplegia, and possibly nausea, vomiting, and neck stiffness
Other Ophthalmology articles in this blog:
“Amblyopia - AKA Lazy Eye” by Emily Groenendaal, MD, and George J Florakis, M.D.
"A look at four common eye maladies: Arcus Senilis, Ectropion, Pterygium, and Pinguecula" by Evan Mostafa, MD and George J.Florakis, MD
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