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<< An Evidence-Based Approach To Abnormal Vision
Unilateral Painful Visual Disturbance
The areas of the eye that are sensitive to pain are the cornea, iris, and ciliary body, as well as the periorbitaltissues. Any inflammatory or infectious process that involves these areas will result in some discomfort or pain.2 The retina, optic nerve, and vitreous are relatively insensitive to pain.
Optic Neuritis
Presentation And Examination Findings
Optic neuritis is typically heralded by a dull retro-orbital ache, followed in the next day or so with monocular blurred vision. It is usually subacute in onset, with a nadir over hours to days, and is associated with pain on eye movement in 92% of patients.2,32-33,37-38,105On examination, there may be varying degrees of compromised visual acuity, and a central visual field defect is typical; an afferent papillary defect may be present, and papilledema or swelling may be visible on fundoscopy if the nerve is affected anteriorly (Figure 8) but is absent initially in about 70% of patients because the process is primarily retrobulbar.2,32,37-38
Diagnostic Workup And Management
The most comprehensive work on the clinical assessment and management of optic neuritis comes from the Optic Neuritis Treatment Trial, a multicenter, randomized, controlled trial funded by the National Eye Institute.33 The diagnosis of optic neuritis is a clinical one based on history and fundoscopic examination and will likely be significantly aided by ophthalmological consultation. Gadolinium-enhanced MRI of the orbits (with fat saturation) is useful in cases in which the diagnosis is suspected but uncertain, as it will highlight the inflammation and swelling of the optic nerve and can delineate high-risk multiple sclerosis lesions if imaging of the brain is also included. 32,106 Other diagnostic modalities, such as searching for oligoclonal bands in CSF and assessing visual evoked potentials,32are impractical in the ED setting.
The prognosis of optic neuritis is generally good but return of visual function is almost never complete.32,107-108 Current guidelines refer to treatment with high-dose steroids.109-110A meta-analysis of 12 randomized, controlled, clinical trials found that steroids resulted in early but non-sustained improvement in visual acuity.111 It has also been associated with a decrease in the incidence of subsequent development of multiple sclerosis at two years, although this does not appear to be a sustained effect beyond that time point.32,34,108
Acute Glaucoma
Presentation And Examination Findings
The patient with an acute elevation in intraocular pressure from glaucoma typically presents with a boring, ocular, or peri-ocular pain with nausea and/or vomiting and blurred vision in the context of a history of intermittent blurring of vision with halos. Examination findings will typically be notable for corneal injection, corneal epithelial edema, elevated intraocular pressure (IOP) over 21 mmHg, and - with acute angle-closure glaucoma - a mid-dilated unreactive pupil and a shallow anterior chamber.112-113 With significantly elevated IOP, the globe may feel firmer than the normal eye when digitally palpated.114-115
Diagnostic Workup And Management
While open-angle and closed-angle glaucoma have slightly different etiologies, their acute treatment in the ED is initially the same and is centered on medical treatment as a temporizing measure until definitive ophthalmological treatment can be arranged. In the case of open-angle glaucoma, the patient can be symptomatically stabilized using a medical regimen of topical and systemic medications, see Table 3.
In the case of acute closed-angle glaucoma, definitive treatment will require evaluation by an ophthalmologist emergently, unless initial medical therapy results in acute and complete improvement. A recent evidence-based review of the literature regarding available therapies for closed-angle laucoma found mostly class III evidence. Laser peripheral iridotomy was a Level A recommendation, supplemented by topical administration of timolol and latanoprost which was a Level B recommendation.113
Corneal Infections, Ulcers, And Abrasions
Presentation And Examination Findings
Corneal processes such as abrasion, infection, and ulceration typically present with eye pain and a red eye and may have obscured vision.2The presence of flare (from hypopyon) or iritis suggests infection over abrasion and a defect, with “heaped up” edges on fluorescein staining suggesting an acute infectious ulceration (keratitis), see Figure 9. Herpes simplex keratitis (the most common viral keratitis) may have a dendritic or geographic appearance on fluorescein staining, see Figure 10.
Diagnostic Workup And Management
The diagnosis of the process that is causing an acute corneal abnormality is essentially achieved on examination, and the management implemented is based on whether the examination findings suggest a corneal abrasion, an infectious corneal ulcer, or a herpetic viral infection.
A recent meta-analysis of randomized, controlled trials found that topical non-steroidals reduce selfreported pain from corneal abrasions,116and a review for the Cochrane Database found that the use of eye patches actually slows corneal healing in the first day and does not reduce patient discomfort over the subsequent days.117Simple corneal abrasions can be discharged to follow-up with an ophthalmologist with topical antibiotic prophylaxis to prevent complications from bacterial superinfection and topical non-steroidals; they should avoid patching.
A recent Cochrane Database review found that the use of topical antibiotics for simple bacterial conjunctivitis improves rates of clinical and bacterial remission but has a marginal impact on actual outcome of the infection itself (since bacterial conjunctivitis is generally a self-limited problem).118BOn the other hand, an ulcerative bacterial keratitis represents a more fulminant infection in which topical antibiotics have a significant impact on outcome; patients with this finding should be urgently referred to an ophthalmologist and treated emergently. Contact lens wearers should be treated with topical antibiotics with coverage for Pseudomonas, as this pathogen has been shown to be present in about 50- 60% of corneal infections in this patient population. 118-119For herpes simplex keratitis, treatment with topical antivirals (such as acyclovir) has been clearly shown to improve corneal epithelial healing in clinical trials, as confirmed in a review for the Cochrane Database;120 institute treatment immediately, and refer the patient urgently to an ophthalmologist.
Endophthalmitis
Presentation And Examination Findings
The patient with endophthalmitis presents with pain out of proportion to the clinical examination, photophobia, and visual loss, typically about six days or so after routine eye surgery such as a cataract removal,121-122 or after trauma.123There may be no precipitant in endogenous endophthalmitis. The examination may be subtle or may be notable for lid edema, hypopyon, conjunctival erythema and edema, corneal edema, and obscuration of the fundoscopic view.123
Diagnostic Workup And Management
The mainstay of treatment of endophthalmitis is the immediate administration of intravitreal antibiotics and vitrectomy; therefore, emergent consultation with an ophthalmologist is necessary. The bacterial species in the majority of post-surgical and post-traumatic cases of endophthalmitis is staphylococcal121-123 so a regimen of intravenous antibiotics that includes staphylococcal coverage, such as ceftazidime 1 gram IV every 12 hours and vancomycin 1 gram IV every 12 hours, should also be administered.123
Cavernous Sinus Thrombosis
Presentation And Examination Findings
The most common signs of cavernous sinus thrombosis are due to fulminant infection and compression of the nerves that run through the sinus and are progressive, involving fever, ptosis, proptosis, chemosis, and cranial nerve palsies in 80% of patients; lethargy,periorbital edema, headache, papilledema, and venous engorgement in 50–80% of patients;decreased visual acuity, sluggish or dilated pupil (due to affected parasympathetic fibers), periorbital sensory loss, decreased corneal reflex (due to CN V involvement), and nuchal rigidity in less than 50% of patients; and diplopia, seizures, and hemiparesis in less than 20% of patients.57 Involvement of the contralateral eye is typical by about 12-24 hours.
Diagnostic Workup And Management
Contrast CT with 3 mm slices may reveal bulging cavernous sinus with lateral wall flattening or convexity rather than normal concavity or filling defects (thrombosis),57,124 but an MRI venogram is considered a more sensitive imaging modality59,125 (although no distinct head-to-head trials have been performed) and has the added benefit of highlighting carotid artery involvement and dural sinus thrombosis.57-58 Blood cultures may be positive in 80% of cases (especially fulminant cases), and a lumbar puncture will reveal CSF with elevated protein and WBC in most patients but will be culture positive in only 20%.57
Staphylococcus aureus is the causative organism in 60–70% of cases of septic cavernous sinus thrombosis with organisms such as streptococcus pneumoniae, gram-negative bacilli, and anaerobes being less common. 57-58 Anticoagulation with warfarin or heparin started within seven days of onset may theoretically improve morbidity,57,125B-126but no randomized trials have been conducted. The use of steroids, though with some suggestion of benefit in improving cranial nerve dysfunction and persistent orbital congestion, is unsupported.57
Uveitis Or Iritis
Presentation And Examination Findings
A patient with anterior uveitis (or iritis) may present with photophobia, eye pain, and slightly blurred vision. On examination, the patient may have the proverbial “red eye,” with signs of conjunctivitis or scleritis and may have a hypopyon 9,70 and pain on direct and consensual light reflex. The pupil may be miotic, presumably due to inflammatory synechiae, but a normal pupil does not exclude an acute iritis.127
Diagnostic Workup And Management
The diagnosis of iritis is a clinical one based on examination. The goals of acute treatment are twofold. The first goal is provision of comfort to the patient and prevention of complications from synechiae, achieved by administering cyclopegics (such as atropine) or mydriatics (such as phenylephrine), one or two drops three to six times a day until inflammation is completely controlled.9 Sightthreatening complications from anterior uveitis include keratopathy, synechiae, and glaucoma (from debris);70 therefore, the second goal of treatment is to reduce inflammation, usually with topical corticosteroids Such as betamethasone, dexamethasone, or prednisolone, given every one to two hours until inflammation is under control.9,128
Optic Neuritis
Presentation And Examination Findings
Optic neuritis is typically heralded by a dull retro-orbital ache, followed in the next day or so with monocular blurred vision. It is usually subacute in onset, with a nadir over hours to days, and is associated with pain on eye movement in 92% of patients.2,32-33,37-38,105On examination, there may be varying degrees of compromised visual acuity, and a central visual field defect is typical; an afferent papillary defect may be present, and papilledema or swelling may be visible on fundoscopy if the nerve is affected anteriorly (Figure 8) but is absent initially in about 70% of patients because the process is primarily retrobulbar.2,32,37-38
Diagnostic Workup And Management
The most comprehensive work on the clinical assessment and management of optic neuritis comes from the Optic Neuritis Treatment Trial, a multicenter, randomized, controlled trial funded by the National Eye Institute.33 The diagnosis of optic neuritis is a clinical one based on history and fundoscopic examination and will likely be significantly aided by ophthalmological consultation. Gadolinium-enhanced MRI of the orbits (with fat saturation) is useful in cases in which the diagnosis is suspected but uncertain, as it will highlight the inflammation and swelling of the optic nerve and can delineate high-risk multiple sclerosis lesions if imaging of the brain is also included. 32,106 Other diagnostic modalities, such as searching for oligoclonal bands in CSF and assessing visual evoked potentials,32are impractical in the ED setting.
The prognosis of optic neuritis is generally good but return of visual function is almost never complete.32,107-108 Current guidelines refer to treatment with high-dose steroids.109-110A meta-analysis of 12 randomized, controlled, clinical trials found that steroids resulted in early but non-sustained improvement in visual acuity.111 It has also been associated with a decrease in the incidence of subsequent development of multiple sclerosis at two years, although this does not appear to be a sustained effect beyond that time point.32,34,108
Acute Glaucoma
Presentation And Examination Findings
The patient with an acute elevation in intraocular pressure from glaucoma typically presents with a boring, ocular, or peri-ocular pain with nausea and/or vomiting and blurred vision in the context of a history of intermittent blurring of vision with halos. Examination findings will typically be notable for corneal injection, corneal epithelial edema, elevated intraocular pressure (IOP) over 21 mmHg, and - with acute angle-closure glaucoma - a mid-dilated unreactive pupil and a shallow anterior chamber.112-113 With significantly elevated IOP, the globe may feel firmer than the normal eye when digitally palpated.114-115
Diagnostic Workup And Management
While open-angle and closed-angle glaucoma have slightly different etiologies, their acute treatment in the ED is initially the same and is centered on medical treatment as a temporizing measure until definitive ophthalmological treatment can be arranged. In the case of open-angle glaucoma, the patient can be symptomatically stabilized using a medical regimen of topical and systemic medications, see Table 3.
In the case of acute closed-angle glaucoma, definitive treatment will require evaluation by an ophthalmologist emergently, unless initial medical therapy results in acute and complete improvement. A recent evidence-based review of the literature regarding available therapies for closed-angle laucoma found mostly class III evidence. Laser peripheral iridotomy was a Level A recommendation, supplemented by topical administration of timolol and latanoprost which was a Level B recommendation.113
Corneal Infections, Ulcers, And Abrasions
Presentation And Examination Findings
Corneal processes such as abrasion, infection, and ulceration typically present with eye pain and a red eye and may have obscured vision.2The presence of flare (from hypopyon) or iritis suggests infection over abrasion and a defect, with “heaped up” edges on fluorescein staining suggesting an acute infectious ulceration (keratitis), see Figure 9. Herpes simplex keratitis (the most common viral keratitis) may have a dendritic or geographic appearance on fluorescein staining, see Figure 10.
Diagnostic Workup And Management
The diagnosis of the process that is causing an acute corneal abnormality is essentially achieved on examination, and the management implemented is based on whether the examination findings suggest a corneal abrasion, an infectious corneal ulcer, or a herpetic viral infection.
A recent meta-analysis of randomized, controlled trials found that topical non-steroidals reduce selfreported pain from corneal abrasions,116and a review for the Cochrane Database found that the use of eye patches actually slows corneal healing in the first day and does not reduce patient discomfort over the subsequent days.117Simple corneal abrasions can be discharged to follow-up with an ophthalmologist with topical antibiotic prophylaxis to prevent complications from bacterial superinfection and topical non-steroidals; they should avoid patching.
A recent Cochrane Database review found that the use of topical antibiotics for simple bacterial conjunctivitis improves rates of clinical and bacterial remission but has a marginal impact on actual outcome of the infection itself (since bacterial conjunctivitis is generally a self-limited problem).118BOn the other hand, an ulcerative bacterial keratitis represents a more fulminant infection in which topical antibiotics have a significant impact on outcome; patients with this finding should be urgently referred to an ophthalmologist and treated emergently. Contact lens wearers should be treated with topical antibiotics with coverage for Pseudomonas, as this pathogen has been shown to be present in about 50- 60% of corneal infections in this patient population. 118-119For herpes simplex keratitis, treatment with topical antivirals (such as acyclovir) has been clearly shown to improve corneal epithelial healing in clinical trials, as confirmed in a review for the Cochrane Database;120 institute treatment immediately, and refer the patient urgently to an ophthalmologist.
Endophthalmitis
Presentation And Examination Findings
The patient with endophthalmitis presents with pain out of proportion to the clinical examination, photophobia, and visual loss, typically about six days or so after routine eye surgery such as a cataract removal,121-122 or after trauma.123There may be no precipitant in endogenous endophthalmitis. The examination may be subtle or may be notable for lid edema, hypopyon, conjunctival erythema and edema, corneal edema, and obscuration of the fundoscopic view.123
Diagnostic Workup And Management
The mainstay of treatment of endophthalmitis is the immediate administration of intravitreal antibiotics and vitrectomy; therefore, emergent consultation with an ophthalmologist is necessary. The bacterial species in the majority of post-surgical and post-traumatic cases of endophthalmitis is staphylococcal121-123 so a regimen of intravenous antibiotics that includes staphylococcal coverage, such as ceftazidime 1 gram IV every 12 hours and vancomycin 1 gram IV every 12 hours, should also be administered.123
Cavernous Sinus Thrombosis
Presentation And Examination Findings
The most common signs of cavernous sinus thrombosis are due to fulminant infection and compression of the nerves that run through the sinus and are progressive, involving fever, ptosis, proptosis, chemosis, and cranial nerve palsies in 80% of patients; lethargy,periorbital edema, headache, papilledema, and venous engorgement in 50–80% of patients;decreased visual acuity, sluggish or dilated pupil (due to affected parasympathetic fibers), periorbital sensory loss, decreased corneal reflex (due to CN V involvement), and nuchal rigidity in less than 50% of patients; and diplopia, seizures, and hemiparesis in less than 20% of patients.57 Involvement of the contralateral eye is typical by about 12-24 hours.
Diagnostic Workup And Management
Contrast CT with 3 mm slices may reveal bulging cavernous sinus with lateral wall flattening or convexity rather than normal concavity or filling defects (thrombosis),57,124 but an MRI venogram is considered a more sensitive imaging modality59,125 (although no distinct head-to-head trials have been performed) and has the added benefit of highlighting carotid artery involvement and dural sinus thrombosis.57-58 Blood cultures may be positive in 80% of cases (especially fulminant cases), and a lumbar puncture will reveal CSF with elevated protein and WBC in most patients but will be culture positive in only 20%.57
Staphylococcus aureus is the causative organism in 60–70% of cases of septic cavernous sinus thrombosis with organisms such as streptococcus pneumoniae, gram-negative bacilli, and anaerobes being less common. 57-58 Anticoagulation with warfarin or heparin started within seven days of onset may theoretically improve morbidity,57,125B-126but no randomized trials have been conducted. The use of steroids, though with some suggestion of benefit in improving cranial nerve dysfunction and persistent orbital congestion, is unsupported.57
Uveitis Or Iritis
Presentation And Examination Findings
A patient with anterior uveitis (or iritis) may present with photophobia, eye pain, and slightly blurred vision. On examination, the patient may have the proverbial “red eye,” with signs of conjunctivitis or scleritis and may have a hypopyon 9,70 and pain on direct and consensual light reflex. The pupil may be miotic, presumably due to inflammatory synechiae, but a normal pupil does not exclude an acute iritis.127
Diagnostic Workup And Management
The diagnosis of iritis is a clinical one based on examination. The goals of acute treatment are twofold. The first goal is provision of comfort to the patient and prevention of complications from synechiae, achieved by administering cyclopegics (such as atropine) or mydriatics (such as phenylephrine), one or two drops three to six times a day until inflammation is completely controlled.9 Sightthreatening complications from anterior uveitis include keratopathy, synechiae, and glaucoma (from debris);70 therefore, the second goal of treatment is to reduce inflammation, usually with topical corticosteroids Such as betamethasone, dexamethasone, or prednisolone, given every one to two hours until inflammation is under control.9,128
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