Evaluation and Management of Sudden Vision Loss: Part I
Evaluation and Management of Sudden Vision Loss: Part I
Sudden vision loss is distressing to most patients; they envision going blind. The challenge to the emergency physician is to identify those disorders in which emergent treatment can save or recover sight. Since many of the disorders discussed in this two-part issue are uncommon, the emergency physician usually does not have enough experience to feel comfortable with most of them. I rely on my ophthalmologist consultant.
Like most specialists, ophthalmologists have their own language — terms that are not in common medical use. I have learned over the years which descriptions and which issues are important to ophthalmologists when discussing a patient over the phone. Telling them that the "the eye is really red and swollen" does not tell them much, nor does it inspire confidence in your assessment skills.
After reading this two-part discussion, you will be better able to talk to your ophthalmologist colleague.
— J. Stephan Stapczynski, MD, Editor
Authors:
Medley Gatewood, MD, Assistant Professor, Division of Emergency Medicine, University of Washington Medical Center, Seattle.
Mitchell Kim, MD, Resident, Division of Emergency Medicine, University of Washington Medical Center, Seattle.
Peer Reviewer:
Jonathan Glauser, MD, Associate Professor, Emergency Medicine, Case Western Reserve University, Cleveland, OH.
Executive Summary
- Determine the best visual acuity: Assess each eye individually, use corrective lenses or pinhole, and use low-vision techniques, if needed.
- Consult the ophthalmologist for most causes of acute vision loss.
- Initiate emergent treatment for acute keratitis and acute glaucoma in the ED.
- Patients with acute anterior uveitis can have their pain controlled with topical cycloplegics until evaluated by an ophthalmologist in 1 to 2 days.
Introduction
Emergency physicians are often consulted by patients experiencing ocular symptoms. It is estimated that more than two million emergency department (ED) visits occur in the United States every year (approximately 3% of total ED visits) due to ocular complaints. Acute vision loss is an especially frightening experience that leads many patients to seek emergency care. Although this symptom is rarely life-threatening, early recognition and treatment of the cause is of paramount importance, as the patient may permanently lose sight in the affected eye(s). Emergency physicians (EPs) should be adept at diagnosing, treating, and obtaining appropriate ophthalmology consultation and follow up for this reason.1,2
Acute vision loss can present on a spectrum from decreased visual acuity (blurred vision) to complete loss of light detection. Anything disrupting the light pathway in the eye, or the neural transmission of this light, can lead to reduced vision. Disease processes that affect visual acuity are grouped based on whether they are associated with pain, affect one or both eyes, or whether they are persistent or transient.
This review will focus on the evaluation and management of atraumatic causes of persistent loss of vision due to ocular pathology. The diseases will be grouped based on whether there is pain associated with the loss of sight. Transient vision loss, often referred to as amaurosis fugax, will be briefly discussed in the context of several disease entities. Chronically progressive vision loss and visual changes related to trauma will not be discussed. Table 1 lists the differential diagnosis of acute vision loss.
Table 1: Causes of Sudden Vision Loss
Ophthalmologic
Painful
- Trauma — globe rupture, corneal injury, hyphema
- Acute angle closure glaucoma
- Infectious keratitis — bacterial, HSV, VZV
- Uveitis
- Optic neuritis
Painless
- Giant cell arteritis
- Vitreous hemorrhage
- Retinal detachment
- Central or branch retinal artery occlusion
- Central or branch retinal vein occlusion
- Ischemic optic neuropathy
Neurologic
- Ocular migraine
- Cerebrovascular accident (CVA) or transient ischemic attack
- Cortical blindness — CVA, posterior cerebral artery aneurysm, congenital/acquired occipital lobe pathology, posterior reversible encephalopathy syndrome (PRES)
- Papilledema — intracranial mass, pseudotumor cerebri, cerebral edema
Toxic/Metabolic
- Hyperglycemia
- Methanol poisoning
Psychiatric
- Conversion disorder
- Factitious disorder
- Malingering
Functional Anatomy
The eyeball, also known as the globe, resides within the orbit that is created by four bony walls that converge posteriorly at the apex. The neurovascular bundles that supply the eye enter the orbit at the apex. The globe itself only occupies about 20% of the volume of the orbit. The other 80% is comprised of mostly muscle and fat. Cranial nerves III, IV, and VI allow for extraocular movements. The oculomotor nerve also provides parasympathetic innervation to the ciliary muscles and iris to allow for accommodation and miosis, respectively. Sensory innervation to the eye is supplied by the branches of the ophthalmic division of the trigeminal nerve.
The ophthalmic artery, which is the first branch of the intracranial portion of the internal carotid artery, provides the principal arterial supply to the orbit and its structures. Its first branch enters the optic nerve to become the central retinal artery, which largely supplies the retina and optic nerve. Various other branches of the ophthalmic artery supply the rest of the globe and form anastomoses with branches of the facial artery. Venous blood from the orbit drains into the superior ophthalmic and inferior ophthalmic veins. These veins ultimately communicate with the cavernous sinus and pterygoid plexus en route to the central venous circulation.3
The globe itself is composed of several layers of tissue that surround a transparent fluid matrix. (See Figure 1.) The bulbar conjunctiva forms the outermost layer that is a continuation of the deepest layer of the eyelids, known as the palpebral conjunctiva. Deep to the conjunctiva is the sclera, which is a protective layer of the eye that is seen as the "white of the eye." The episclera lies between these layers and contains vessels that supply the sclera. The anterior aspect of the globe is formed by the cornea. This attaches to the sclera at the limbus.
Figure 1: Schematic Diagram of the Structures of the Globe
The retina converges at the optic nerve, which then carries the light information to be processed by the brain.
Source: Wikimedia Commons. Author: Rhcastilhos.
Deep to the sclera is the uveal tract, made up of the iris, ciliary body, and choroid. These structures are responsible for pupillary accommodation/constriction and for providing vascular supply to eye. Finally, the retina forms the deepest cellular layer of the globe. It contains neural elements that extend from the optic nerve to the ciliary body anteriorly.4
The sensation of sight begins with light entering the globe through the cornea. It passes through the anterior chamber, which contains the aqueous humor, prior to going through the pupil. The pupil acts as an aperture for light, with its size being governed by the autonomic innervation of the iris. Light then passes through the lens and posterior chamber (containing vitreous humor) prior to reaching the retina. The retina converts light patterns to neural signals, which ultimately go through the visual pathways in the brain. The fovea is the part of the retina directly in line with the light pathway through the pupil and lens. It contains the highest concentration of cones, and provides the highest visual acuity. This visual pathway ultimately allows for the sensation of sight. Any acute lesions along this pathway can lead to sudden impairments in vision.5
Evaluation of Patients with Sudden Vision Loss
Obtaining an expedient, yet fastidious, history and physical examination of the patient presenting with visual disturbances is of paramount importance. The EP should try to determine if the etiology of vision loss is related to a benign cause or to other diseases that can progress to permanent vision loss.
History. The history of present illness should differentiate vision loss from other ocular symptoms, including pain, changes in appearance, or diplopia. Characterize the visual deficit as precisely as possible to aid in diagnosis. Associated symptoms, laterality, onset, duration, and any events thought to have provoked the symptoms should be elicited. The presence of ocular pain helps narrow the differential. Patients should be questioned about toxic ingestions (methanol), ocular trauma, floaters, flashing lights, or a "curtain" obstructing their vision. A history of multiple episodes of transient vision loss may be present in patients with optic neuritis or central retinal artery occlusion. Lastly, a complete review of systems should be performed, as vision loss can be a manifestation of a systemic process. For instance, temporal arteritis can lead to monocular vision loss, which is associated with jaw claudication, headache, or symptoms of polymyalgia rheumatica. A history of palpitations may suggest atrial fibrillation as a cause of vision loss due to embolic phenomenon.4,6
A patient’s history of pathology involving the eye should be obtained. This includes corrective eyewear use and previous eye trauma/surgery. Other chronic medical issues should be explored. A vasculopathic patient is much more susceptible to amaurosis fugax and central retinal artery occlusion. A list of ocular and systemic medications is useful to further characterize a patient’s medical issues. In addition, some medications can result in vision loss as a direct side effect. A family history of any ocular issues may be useful.4,6,7
Ophthalmologic Exam
The following describes the aspects of the ophthalmologic exam. The examination should be performed prior to intervention, except in cases of chemical keratitis in which irrigation takes precedence. A general non-ophthalmologic physical exam should be performed as indicated.
Inspection. The head and eyes should be inspected for any gross abnormalities. Ptosis, exophthalmos, enophthalmos, conjunctival injection, and chemosis should be noted, if present.6
Visual Acuity. Visual acuity, the vital sign of the eye, should be accurately obtained and documented. Obtain this prior to further examination since bright lights can temporarily underestimate true visual acuity. Patients should be allowed to wear their corrective lenses (if applicable) to obtain a corrected visual acuity. If corrective lenses are unavailable, the exam can be performed with the patient looking through a pinhole to eliminate refractive errors; this will approximate the corrected visual acuity.
Each eye should be tested separately using the familiar Snellen chart, with the patient standing 6 meters (20 feet) away from the letters. The patient’s visual acuity is the number (20/20, 20/25, etc.) next to the smallest line in which the patient can read half of the letters correctly. The denominator refers to the distance that a normal eye can read the line, and the numerator is the distance from which the patient is reading the chart.
Illiterate patients, children, and those not familiar with the English alphabet can be tested using an "illiterate E" chart or with the Allen chart, which contains pictures. Patients with very poor vision, too poor to be measured with the Snellen chart, should have their visual acuity described as being able to (in descending order) count fingers at an arm’s length, detect hand motion, or perceive visible light. Patients who have no visible light perception (NVLP) have complete blindness.4,7
Visual Fields. Deficits in the visual fields may imply a retinal or neurological cause of vision loss. This is most commonly done by testing each eye separately by confrontation. This is performed with the physician and patient seated facing each other. Each person covers one eye directly across from each other (i.e., the patient will cover his or her left eye and the physician will cover his or her right eye). The physician uses his or her other hand to present targets halfway between the patient and physician. The patient is instructed to name the target in his or her peripheral vision while focusing vision on the physician’s nose. This is typically performed by asking the patient to count the number of fingers in the four visual quadrants. Monocular visual field deficits are often seen in retinal pathology. Binocular visual field deficits are often due to chiasmal and retrochiasmal disease such as a CVA or pituitary adenoma.4,7
Extraocular Movements (EOM). Assess for dysconjugate gaze prior to the formal EOM exam. The ability to move one’s eyes in the six cardinal directions of gaze is dependent on the normal structure/function of cranial nerves III, IV, and VI, as well as the six extraocular muscles. EOM are tested by instructing the patient to focus his or her eyes on a target (typically the physician’s index finger) as it is moved in a large "H" shape. The range and smoothness of the patient’s eye movements should be noted. Patients should be asked if they have any diplopia during the exam, as this is a subtle finding with extraocular muscle weakness. The diplopia typically happens when the patient is asked to look in the direction of the weak muscle.4,7
Pupils. The pupils first should be examined in a dimly lit room to look for size and shape. Anisocoria, or unequal size of pupils, should be noted, if present. However, the most common cause of anisocoria is idiopathic, and the difference in size is usually less than 1 mm. The normal pupil response to light requires the normal function of the retina, optic nerve, and oculomotor nerve. Shining a penlight into each of the patient’s eyes tests direct and consensual pupillary constriction. In the normal person, both pupils should constrict when light is shined into either eye. In an afferent pupillary defect, the pupil of the involved eye constricts when light is shone into the opposite eye, but then dilates, sometimes only slightly, when the penlight is moved to the involved eye. In an efferent pupillary defect, the pupil of the involved eye does not constrict when the penlight is shone into either eye. Afferent or efferent pupillary defects, if present, typically indicate a lesion in the optic nerve or oculomotor nerve, respectively.4
Fluorescein Exam. Fluorescein is a stain that highlights defects in the corneal epithelium. It should be performed in all cases of ocular trauma, foreign body, or suspected infection. However, it can be a part of any ophthalmologic examination. Its only absolute contraindication is fluorescein allergy. Fluorescein is instilled into the patient’s eye by placing several drops of normal saline onto a fluorescein strip and allowing this to drop into the eyes. Contact lenses should be removed to avoid permanent staining.
In the acidic environment that is typically present in the intact cornea, fluorescein does not light up under a blue light (slit lamp or Wood’s lamp). Fluorescein appears bright green under blue light when it collects into the alkaline corneal defect. Topical anesthetic can be applied prior to the fluorescein exam if photophobia or pain limit eye opening. Fluorescein that appears streaming from an area of the globe is called a positive Seidel’s test, and indicates globe rupture or complete corneal laceration.2
Slit Lamp Exam. The slit lamp provides a magnified, illuminated view of the exposed ocular structures. It is composed of a light source and an eye piece that acts as a microscope to examine the eyes. The eyelashes, eyelids, conjunctiva, sclera, cornea, anterior chamber, and lens can all be examined using the slit lamp. The patient and physician should be seated on adjustable stools, and the patient should be instructed to place his or her chin on the chinstrap. The chinstrap should be adjusted until the canthi of the eyes are level with the black marker on the vertical pole next to the patient’s face. The height of the slit lamp should be adjusted so the patient can place his or her forehead onto the headrest. The joystick can be used to adjust focus by moving the light source and microscope closer or farther away from the patient’s eyes. The size and shape of the light beam should be adjusted until the vertical light beam is roughly the height of the cornea and 1 mm wide.
The examination begins with the light source and ocular source pointed directly at the patient’s eyes. The eyelids and eyelashes can be examined for any abnormalities. The bulbar and palpebral conjunctiva are then examined. Any follicles or foreign bodies should be noted.
At this point, the light source should be rotated until it makes a 45-degree angle to the physician/patient axis. This angle allows the light source to create a cross sectional view of the cornea. Ulcers, precipitates, lacerations, among other corneal pathology, can be seen using this method. The anterior chamber can be examined by adjusting the light source to a 60-degree angle and focusing the beam onto the limbus.
The anterior chamber is the dark region between the iris and the posterior aspect of the cornea. A normal or deep (open) anterior chamber is larger than half the thickness of the cornea. An anterior chamber depth that is less than one-quarter the thickness of the cornea is considered shallow with a dangerously narrow angle. The light beam should be focused on the pupil to look for "cells and flare" often seen in inflammatory conditions. The lens can be evaluated for the presence of cataracts or displacement. A potentially useful mnemonic to remember the aspects of the slit lamp exam is L-L-L-L-L-C-C-C (lids, lashes, limbus, lacrimal structures, lens, cornea, conjunctiva, and chamber).2,4
Intraocular Pressure (IOP). The IOP is measured by tonometry. It is indicated if there is a suspicion for acute angle closure glaucoma (primary or secondary to hyphema), or if there is blunt eye trauma. Tonometry should be avoided if there is suspected globe penetration to prevent further extrusion of globe contents. Normal IOP is 12-20 mm Hg. Therapy for glaucoma should be instituted if IOP is greater than 30 mm Hg in the setting of consistent clinical findings. IOP between 20-30 mm Hg requires urgent ophthalmology consultation.
There are several methods of tonometry. Digital tonometry is done by directly palpating the patient’s globe through the eyelid. The eye with increased IOP will feel harder than the other eye. However, this method is insensitive in excluding elevated IOP, and is more useful as a quick screening test as opposed to an alternative to impression tonometry.
Impression tonometry is the most commonly used modality in the ED to measure IOP. It utilizes a device to determine how much force is required to indent the cornea. There are two main types of impression tonometry used in the ED: the Schiötz tonometer and the handheld Tono-Pen® XL. With either device, the patient’s eyes should be topically anesthetized. To use the Schiötz tonometer, the patient is first placed supine, and instructed to focus on a far-away object. The foot of the Schiötz tonometer is placed directly on the cornea. The resulting number at the top of the tonometer can then be converted to an IOP using a chart. If this number is less than 4 or 5, additional weights should be added to the scale and the procedure repeated. Schiötz tonometry is not well tolerated by patients, and the equipment is difficult to sterilize. For this reason, a Tono-Pen® XL or a similar device is often used in the ED. The Tono-Pen® XL comes with disposable covers. It is touched to the cornea 4-10 times, and the reading is an average of the IOP levels that are measured. Other methods, including applanation and pneumatic tonometry, are less often used in the ED.2,4
Fundoscopy. The vitreous, optic nerve, and retinal structures can be examined via ophthalmoscopy. The EP can perform direct ophthalmoscopy using a handheld ophthalmoscope. The discussion of ophthalmoscopy will be limited to the direct technique, as the EP does not typically use indirect ophthalmoscopy. The positive numbered (black) lenses can be used to visualize the anterior structures, including the cornea and lens. The negative (red) numbered lenses are used to visualize the fundus.
The exam begins by darkening the room and dilating the pupil with one drop of topical anticholinergic (i.e., 1% tropicamide) in Caucasian patients. In addition, a drop of topical alpha agonist (i.e., 2.5% phenylephrine) may be required for adequate dilation, especially in non-Caucasian patients. Chemical pupillary dilation should be performed in all patients without concern for glaucoma, since it provides a much better view of the fundus than a non-dilated pupil.
The patient should be asked to focus on an object straight ahead, while the physician brings the ophthalmoscope into focus and finds the "red reflex" through the pupil. The physician then moves closer to the patient until the retinal vessels are seen. The retinal vessels should be examined for any lesions (exudate, hemorrhage, etc.), loss of spontaneous venous pulsations, and followed proximally to the optic disc. The optic disc margins should be examined, and cupping should be noted, if present. The macula should be located and examined. The presence of cataracts or vitreous hemorrhage may obscure the visualization of the fundus. A normal fundoscopic exam is shown in Figure 2.4,7
Figure 2: The Normal Fundoscopic Exam
Note the sharp optic disc margin to the left, central macula, and the appearance of retinal vessels.
Source: Wikimedia Commons. Credit: National Eye Institute, National Institutes of Health. Ref#: EDA06.
Ultrasound. The ocular ultrasound is an adjunct to the physical exam that can be performed quickly at the bedside by an EP. It can be used to diagnose retinal detachment, vitreous hemorrhage, retrobulbar hematoma, lens dislocation, intraocular foreign body, globe rupture, and central retinal vessel occlusion. It is accurate, rapidly performed, and can provide additional useful information in conjunction with the physical exam.
A linear 7.5-10 MHz probe is used to perform this exam. Copious amounts of ultrasound gel should be applied to the patient’s closed eyelids. The probe is gently placed on the orbit, and the images are obtained by fanning the probe through the orbit in the sagittal and axial planes. A dislocated lens or foreign body will appear as such on the images. A retinal flap may be seen in vitreous hemorrhage and retinal detachment. Color Doppler flow may be absent in the optic nerve in central retinal artery occlusion. Several studies have shown that a dilated optic nerve sheath diameter greater than 5 mm is associated with optic neuritis. Further studies in the field of EP-performed ocular ultrasound will determine other uses and limitations of this diagnostic modality.2,8,9
Acute Painful Vision Loss
Infectious Keratitis. A 74-year-old woman with a history of cold sores presents with blurred vision in her left eye since she woke up this morning. She states that she had some pruritis and discharge from her left eye yesterday. She complains of left eye pain, foreign body sensation, and inability to open her left eye due to photophobia. Her corrected visual acuity is 20/40 OD and 20/60 OS. A slit lamp exam with fluorescein shows injected conjunctiva and a dendritiform ulcer on the left cornea at the 5 o’clock position. The IOP and fundoscopic exam are within normal limits.
Etiology. Infectious keratitis occurs when a microorganism colonizes and proliferates within the corneal stroma. The etiological agent may directly infiltrate through the corneal epithelium, or may be seeded through a traumatic injury. Inflammation of the cornea, known as keratitis, may also be due to damage from exposure, ultraviolet rays, medications, or autoimmune disease. Herpes simplex virus (HSV), varicella zoster virus (VZV), bacteria (staphylococcus, pseudomonas), fungi, and parasites (acanthamoeba sp) are all causes of infectious keratitis that may present to the emergency department. HSV, VZV, and bacterial keratitis will be further discussed in detail. Early recognition and treatment are necessary to prevent sequelae of these infections, including permanent corneal scarring and vision loss in the affected eye.10,11
Clinical Presentation. The cornea is richly innervated, and irritation due to inflammation from any etiology causes significant symptoms. (See Table 2.) Patients typically present with photophobia, eye pain, tearing, foreign body sensation, and conjunctival injection. Vision may be affected if the inflammation is localized over the visual axis, or secondary to other symptoms. Past medical history may be significant for recurrent ocular infections, immunosuppression, contact lens use, and use of ocular medications. Topical anesthetic is often required to get an adequate exam on patients, as they often have trouble opening their eyes due to pain. The exam will typically show injected conjunctiva, discharge (which may be purulent), and corneal epithelial defects.10
Table 2: Infectious Keratitis Pearls
- Moderate to severe pain is common.
- Significant pain relief can be achieved with topical tetracaine.
- Urgent ophthalmologic consult is important for collection of appropriate specimens and initiation of anti-infective treatment.
Herpes keratitis can be associated with a vesicular rash around the affected eye. Dendritiform ulcers on the cornea are characteristic of HSV keratitis. If untreated, these progress to "geographic ulcers."12 Ocular involvement from the VZV is referred to as herpes zoster ophthalmicus (HZO). Patients will have a prodrome of neuropathic symptoms along the distribution of the V1 branch of the trigeminal nerve. This is followed by an eruption of vesicles in the same dermatome. Patients may have systemic symptoms during an episode. On exam, patients can have a vesicle at the tip of the nose known as Hutchinson’s sign. They may have dendritiform ulcers (pseudodendrites) in the cornea. Cell and flare may be present if there is iritis, and retinal lesions are apparent if it is involved. Regardless of the specific organism, bacterial keratitis typically presents with purulent discharge from the eye with suppurative ulceration of the cornea.10
Management. All causes of infectious keratitis require the institution of immediate treatment to prevent further destruction of the cornea. The patient should be evaluated by an ophthalmologist in the ED or within 1-2 days to ensure appropriate response to treatment and to confirm diagnosis, as different causes of infectious keratitis have differing treatments. The management of HSV, VZV, and bacterial keratitis will be discussed in further detail.4
HSV Keratitis. The diagnosis of herpes keratitis is often made by clinical findings. Culture of the lesion is considered the gold standard for diagnosis, but it is an insensitive test. Corneal samples can be sent for HSV PCR, which is a much more sensitive test. Topical antivirals are the mainstay of treatment for HSV keratitis. One percent topical trifluridine (Viroptic), 0.15% topical ganciclovir, and 3% topical acyclovir (only available in Europe) are considered almost equal in efficacy. Topical idoxuridine or vidarabine is considered less effective, but may be considered in allergic patients. Topical erythromycin can be added if there is a concern for bacterial superinfection. Oral acyclovir is considered equally effective as topical agents, and may be preferred to ensure compliance in certain populations. Physical scraping of lesions (treatment of choice prior to antivirals) and topical interferon are not routinely used. Patients should be referred to an ophthalmologist within one to two days.4,14
Herpes Zoster Ophthalmicus. HZO is primarily diagnosed based on clinical findings. When possible, patients with corneal involvement should be seen by an ophthalmologist within 24 hours. The diagnosis can be confirmed with corneal scrapings via Tzanck smear or culture. The mainstay of treatment is with oral antivirals. Acyclovir, famciclovir, or valacyclovir for seven days is the typical regimen. All three are considered equal in terms of efficacy, but the latter two have the benefit of a simpler dosing regimen. Treatment for HZO is of greater efficacy if started within three days, although some benefit is seen if treatment is started up to a week after onset. The emergency physician may have to initiate therapy with one of the oral antivirals. Cutaneous and intraocular erythromycin ointment can be used to prevent bacterial superinfection. Pain can be controlled with a topical cycloplegic, such as cyclopentolate. Topical steroids are considered useful if there is coexistent iritis, but an ophthalmologist evaluation is recommended before starting them.
Admission is advised for those who are immunocompromised, have systemic herpes zoster infection, or have cranial nervice palsies.4,13
Bacterial Keratitis. Patients with a concern for bacterial keratitis should be emergently referred to an ophthalmologist. Corneal scrapings should be sent for gram stain and culture if possible. Treatment with broad-spectrum topical antibiotics to cover gram-positive cocci and Pseudomonas should be initiated expeditiously. Fluoroquinolones (ciprofloxacin, ofloxacin) or aminoglycosides (tobramycin, gentamicin) are considered first-line treatments. Additional gram-positive coverage with vancomycin or cefazolin may be considered. There is debate over the use of topical corticosteroids in the ophthalmologic literature, and the decision to use steroids should be made in conjunction with an ophthalmologist. Do not patch the affected eye; fulminant corneal necrosis may occur if there is a pseudomonal infection.4,11
Acute Angle Closure Glaucoma. A 67-year-old man with a history of diabetes mellitus presents with sudden vision loss in his left eye. This began as the lights were dimmed in a movie theater. He complains of associated left-sided headache, vomiting, and abdominal discomfort. He is only able to count fingers at arm’s length through his left eye. A slit lamp shows corneal edema, mid-dilated and fixed pupil, and conjunctival injection. Tonometry shows an IOP of 68 mm Hg.
Etiology. Glaucoma is a disorder characterized by impairment of aqueous humor outflow, leading to increased intraocular pressure. The most common type of glaucoma is chronic, with slowly progressive increasing intraocular pressure. This form of glaucoma is painless. The less common form, acute glaucoma, is associated with a shallow anterior chamber and a narrow angle at the junction of the cornea and iris. The sudden blockage of aqueous humor drainage seen in an acute attack is very painful, often with associated systemic symptoms. If untreated, the increased IOP causes optic neuropathy and permanent vision loss. It is considered the world’s most common cause of irreversible blindness, with 60 million people affected. It occurs more commonly in older Asian or Eskimo women.15,16
Aqueous humor is produced by the ciliary bodies. It travels through the pupil into the anterior chamber. It becomes reabsorbed into the systemic circulation by entering the trabecular meshwork at the angle of the peripheral cornea and iris. Glaucoma is classified as open angle if this angle remains patent, and closed angle if the iris bows anteriorly to obstruct the trabecular meshwork. This can occur primarily, or secondary to certain processes such as hyphema. Whereas open angle glaucoma typically causes chronic vision loss, acute-angle closure glaucoma is an emergent condition that can rapidly lead to vision loss.16
Clinical Presentation. Acute angle closure glaucoma typically presents with acute, painful vision loss. Patients typically complain of blurred vision with halos surrounding lights. Headache, nausea or vomiting, and abdominal pain are often present. The diagnosis can be challenging in atypical cases with painless vision loss, or when patients present with isolated abdominal symptoms. Certain sympathomimetic and anticholinergic medications or drugs are known to provoke acute angle closure. These include bronchodilators, nasal decongestants, cocaine, and antidepressants (i.e., tricyclic antidepressants, selective serotonin reuptake inhibitors). Topiramate is known to induce acute angle closure as an idiosyncratic reaction.16,17
Patients have decreased visual acuity and a narrow anterior chamber on exam. A slit lamp exam may show corneal edema (a "steamy" or "cloudy" cornea), a mid-dilated, fixed pupil, and conjunctival injection. (See Figure 3.) Their globe may feel firm. The hallmark of glaucoma is elevated IOP (> 20 mm Hg), which may be as high as 70-80 mm Hg.15,17
Figure 3: Acute Angle Closure Glaucoma
Note the mid-dilated pupil, corneal edema, and conjunctival injection.
Source: Wikimedia Commons. Credit: "The Eyes Have It" by Jonathan Trobe, MD.
Management. Once the diagnosis is made based on clinical presentation and IOP, patients should be emergently referred to an ophthalmologist. Patients should immediately be started on medical treatment, especially if their IOP is greater than 40 mm Hg, since these pressures can lead to rapid vision loss. ED treatment aims to rapidly lower IOP. Acute glaucoma is treated with a combination of agents, including systemic carbonic anhydrase inhibitors, topical beta-blockers, topical alpha-agonists, topical cholinergics, intravenous osmotic diuretics, topical prostaglandins, and systemic glucocorticoids. A variety of drug treatment protocols have been published, but there is no evidence that one specific regimen is superior. The key is multiple agents, aggressive dosing, and frequent IOP monitoring. IOP should be rechecked regularly. Definitive treatment with laser iridotomy or peripheral iridectomy may be required if IOP fails to resolve with medical treatment.15,16
Table 3: Medical Treatment of Acute Glaucoma
- Acetazolamide (carbonic anhydrase inhibitor): 500 mg PO (if not nauseated) or IV (if nauseated)
- Timolol (beta-blocker): 0.5% concentration, 1 drop in involved eye, repeat in 1 hour if IOP elevated > 30 mmHg, and continue every 12 hours thereafter
- Apraclonidine (alpha-agonist): 1% concentration, 1 drop in involved eye, repeat in 1 hour if IOP > 30 mmHg
- Mannitol (osmotic diuretic): 20% solution, 2.5 to 10 mL/kg IV one dose
- Pilocarpine (cholinergic): 2% solution, 1 drop in involved eye every 15-60 min., may repeat up to four times; some experts recommend delaying this agent until the IOP is < 40 mmHg
Anterior Uveitis. A 27-year-old man with a history of Crohn’s disease presents with blurry vision in his right eye for three days. His visual acuity has been progressively worsening. He also complains of photophobia, right eye pain, and right eye redness. The patient’s corrected visual acuity is 20/200 OD, and 20/25 OS. He has limbic injection, hypopyon, and anterior chamber cell/flare on slit lamp exam. His IOP and fundoscopic exam are within normal limits.
Etiology. Anterior uveitis refers to the inflammation of the iris and/or ciliary bodies. When the iris or ciliary bodies are affected in isolation, it is referred to iritis or cyclitis, respectively. If both structures are inflamed, it is known as iridocyclitis. Anterior uveitis is much more common than posterior uveitis (inflammation of the choroid) in the United States. Its yearly incidence is approximately 17 per 100,000 persons. The most common age at presentation is 20-50 years old. Most cases of anterior uveitis are idiopathic. When an etiology is identified, it is most often HLA-B27-associated anterior uveitis (HLA-B27 AAU). This may be associated with other HLA-B27-associated diseases, such as ankylosing spondylitis, Reiter’s syndrome, or IBD-related arthropathy. Other causes of anterior uveitis include sarcoidosis, trauma, Behçet’s disease, juvenile rheumatoid arthritis, and Kawasaki disease. Tuberculosis, syphilis, VZV, and HSV are some infectious causes of anterior uveitis.15,18
Clinical Presentation. Many patients with anterior uveitis present with conjunctival injection, chemosis, vision loss, eye pain, and photophobia. Symptoms have an acute or chronic course. Both eyes may be affected in systemic disease. Ocular discharge and pruritus are uncommon. Patients have decreased visual acuity, and slit lamp exam confirms the diagnosis. Limbic congestion, hypopyon, and cell/flare within the anterior chamber are all consistent with anterior uveitis. Consensual photophobia is often present due to the inflammation of the iris. Pain of anterior uveitis is not significantly improved with topical local anesthetics such a tetracaine. Patients with uveitis from a systemic disease may have other symptoms corresponding to the underlying condition.4,19
Management. Diagnosis is based on clinical findings. Patients diagnosed with anterior uveitis should be referred to an ophthalmologist within one to two days for further management. They should be referred to their primary care provider or a specialist for further management of their underlying disease, if present. ED treatment for idiopathic uveitis is primarily aimed at controlling symptoms until patients can be seen for further work up. This can be done with topical cycloplegics such as homatropine or tropicamide.
The underlying infectious or inflammatory disorder should be treated. It is important to note that syphilitic anterior uveitis should be treated as neurosyphilis. Topical/systemic corticosteroids are often used to treat this disorder, but their use should not be initiated in the ED without ophthalmologic consultation. Patients with severe anterior uveitis are also treated with immunosuppressive medication (methotrexate, azathioprine) and biologic agents (infliximab, etanercept) in the outpatient setting.4,19
Table 4: Summary of Painful Vision Loss
| Disease | Cause(s) | Presentation | Physical Findings | ED Treatment/Management | Disposition |
|---|---|---|---|---|---|
|
Infectious keratitis |
1. Bacterial (Staphylococcus, Pseudomonas) 2. Viral (herpes simplex virus, varicella zoster virus) 3. Amoebic (Acanthamoeba sp.) |
Vision loss, ocular pain, photophobia, purulent discharge |
Bacterial: Suppurative ulceration on slit lamp HSV: Dendritiform ulcers progressing to geographic ulcers on slit lamp VZV: Hutchinson's spot, vesicular rash along the V1 dermatome, dendritiform ulcers on slit lamp |
Bacterial: Corneal scrapings for culture. Treatment is with topical antibiotics:
HSV: Topical antivirals
VZV: Oral antivirals
|
Bacterial: Immediate ophthalmology evaluation HSV: Ophthalmology follow-up within 1-2 days VZV: Immediate ophthalmology evaluation. Consider admission in immunocompromised or systemically ill patients |
|
Acute angle closure glaucoma |
Closure of the angle between the iris and peripheral cornea, leading to increased IOP |
Acute onset vision loss, eye pain, nausea, vomiting, headache, abdominal symptoms |
|
Decrease IOP
|
Immediate ophthalmology evaluation |
|
Anterior uveitis |
Idiopathic, trauma, infectious, or part of a systemic inflammatory disease |
Acute to subacute vision loss, eye pain, photophobia |
|
Symptomatic treatment
|
Ophthalmology follow-up in 1-2 days Appropriate outpatient follow-up for underlying disease |
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