REVIEW ARTICLE Differentiating Urgent and Emergent Causes of Acute Red Eye for the Emergency Physician Christopher J. Gilani, BS* *University of California, Irvine School of Medicine, Irvine, California Allen Yang, BS† †Western University of Health Sciences, College of Osteopathic Medicine of Marc Yonkers, MD, PhD‡ the Pacific, Pomona, California Megan Boysen-Osborn, MD, MHPE§ ‡University of California, Irvine, Medical Center, Gavin Herbert Eye Institute, Department of Ophthalmology, Irvine, California §University of California, Irvine, Medical Center, Department of Emergency Medicine, Orange, California Section Editor: Eric Snoey, MD Submission history: Submitted July 26, 2016; Accepted December 30, 2016 Electronically published March 3, 2017 Full text available through open access at http://escholarship.org/uc/uciem_westjem DOI: 10.5811/westjem.2016.12.31798 Patients commonly present with an acute red eye to the emergency department (ED). It is important to distinguish between benign and sight-threatening diagnoses. Here we provide a comprehensive overview on the acute red eye in the ED. [West J Emerg Med. 2017;18(3)509-517.] INTRODUCTION scleritis, anterior uveitis). Photophobia can either be direct, Emergency physicians (EP) must be knowledgeable in consensual, or both. Direct photophobia refers to pain the evaluation of the acute red eye. For the purposes of this with light shone in the affected eye; whereas, consensual review, the acute red eye refers to a patient with conjunctival photophobia refers to pain with light shone in the unaffected and/or scleral redness. The differential diagnosis ranges eye. Consensual photophobia, though a subjective finding, is from routine (subconjunctival hemorrhage) to immediately suggestive of iritis (anterior uveitis) over superficial corneal sight-threatening diagnoses (acute angle closure glaucoma processes.3 Corneal abrasions may present with severe pain, [AACG] or endophthalmitis). Asking key historical questions but the pain typically subsides in 24-48 hours and patients and performing a complete ocular examination will help will have a characteristic lesion on fluorescein examination.4 to distinguish whether emergent, urgent, or as-needed Patients with corneal abrasions from contact lenses should ophthalmologic follow up is necessary. Here we discuss key routinely see an ophthalmologist within 24-48 hours, historical and physical examination features in the workup of especially if symptoms have not improved.4 the acute red eye. We provide a comprehensive overview of the differential diagnosis for the patient who presents to the Associated Symptoms emergency department (ED) with an acute red eye. The EP should determine if the patient has any associated symptoms, such as headache or vomiting, concerning for HISTORICAL FEATURES AACG.5 Symptoms of an upper respiratory tract infection are Pain or Photophobia often associated with viral conjunctivitis.1 Pain and/or photophobia are important features in distinguishing between minor and serious ophthalmologic History of Trauma, Exposure, or Surgery diagnoses. Mild irritation or foreign body sensation may be A history of minor trauma should raise suspicion for present in minor diagnoses (conjunctivitis, episcleritis).1,2 a corneal abrasion or subsequent infectious keratitis.4,6 Early viral keratitis, however, may present with irritation only. Physicians should be concerned for an ocular foreign body It is important to perform a thorough skin and fluorescein in metal workers or ultraviolet (UV) keratitis in patients with examination in these patients. Physicians should take caution exposure to the sun or occupational UV light.7 A history of in any patient who has pain or photophobia, as these can be moderate or major trauma should raise suspicion for globe signs of more serious diagnoses (AACG, bacterial keratitis, rupture or traumatic iritis.8,9 The EP should strongly consider Volume 18, NO. 3: April 2017 509 Western Journal of Emergency Medicine Differentiating Causes of Acute Red Eye for the EP Gilani et al. endophthalmitis in a patient with recent ophthalmologic Response to Topical Anesthetic surgery.10 Chemical burns or chemical conjunctivitis are Instillation of proparacaine or other anesthetic eye the result of ocular chemical exposure; identification of the drops should significantly improve symptoms if the pain is chemical content of the exposure and possible acidity or secondary to a lesion at the corneal or conjunctival surface, basicity may aid therapy. such as a corneal abrasion. Improvement of pain following topical anesthetic administration is reassuring; however, Risk Factors corneal ulcers/bacterial keratitis, foreign bodies, and viral Episcleritis, scleritis, and anterior uveitis are associated keratitis must still be considered. While some studies with autoimmune and rheumatologic conditions.2 Patients have supported the practice of discharging patients home with a history of contact lens use are at an increased risk with a short course of topical anesthetics,12-14 we do not for infectious keratitis.11 Medication history may also guide recommend this as routine practice, as their use is toxic to diagnosis; for example, anticoagulants are associated with the corneal epithelium and can potentially result in severe subconjunctival hemorrhage, while topiramate is associated complications.15,16 with angle closure. Response to Phenylephrine PHYSICAL EXAMINATION FEATURES Although we do not routinely instill phenylephrine Skin and Lid Examination drops to all patients with an acute red eye, the response to In a patient with an acute red eye, herpetic lesions on phenylephrine is useful in distinguishing between episcleritis the skin warrant further investigation for herpes or varicella and scleritis.2 The redness of episcleritis should improve keratitis by fluorescein and slit lamp examination.8 If there is with instillation of phenylephrine, as the episcleral vessels confirmed or high suspicion for herpes or varicella keratitis constrict, but the redness of scleritis should not improve.2 patients should be started on oral or topical antivirals in Phenylephrine should be instilled only after accurate normal the ED. The patient should have urgent (24-48 hours) intraocular pressure (IOP) has been determined, so as to not follow up with ophthalmology to determine the extent of exacerbate AACG.17 ocular involvement. If antiviral treatment is not initiated, ophthalmologic follow up or consultation should be within 12 Slit Lamp Examination hours. Erythema or edema of the skin should raise suspicion A slit lamp examination is necessary to identify cells for periorbital cellulitis, dacrocystitis, stye, or blepharitis, and flare in the anterior chamber, as this is a sign of an acute which may have associated conjunctivitis. More serious inflammatory process, such as anterior uveitis or bacterial causes of an acute, red painful eye with periorbital edema keratitis.11 While up to 75% of patients with bacterial keratitis and erythema are orbital cellulitis and cavernous sinus will not have anterior chamber inflammation,18 cell and thrombosis, which may present with pain on eye movement or flare in the anterior chamber warrant urgent ophthalmologic ophthalmoplegia. It is also important to examine underneath consultation.11 The EP can assess for anterior chamber the lid (“flipping the lid”) in patients with a corneal epithelial inflammation at the slit lamp by setting the slit beam at a small defect (positive fluorescein staining often vertically oriented) 1x1 mm beam and projecting it at an oblique angle through to ensure that there is no retained foreign body, causing the anterior chamber. Inflammation is characterized by the repetitive trauma to the eye. presence and density of circulating immune cells (cell) and a foggy appearance to the slit beam (flare) caused by protein Visual Acuity leaking into the anterior chamber through inflamed vessels. An assessment of visual acuity (VA) should be performed The slit lamp will also identify a corneal infiltrate associated in all patients presenting with ocular complaints. The with bacterial or fungal keratitis. patient should wear his/her own corrective lenses for the exam with distance or near correction as necessary.9 If the Fluorescein Examination patient does not have corrective lenses, a practitioner can In conjunction with the slit lamp examination, fluorescein perform a VA with pin holes to compensate for refractive will identify a corneal epithelial defect, such as a corneal error. When administering a visual acuity exam, patients abrasion or a corneal defect associated with a microbial should be encouraged to give their best “guess” for each keratitis infiltrate. UV keratitis can present with diffuse line. For patients with significant discomfort due to a corneal punctate staining. Branching lesions with end bulbs that abrasion, the VA should be checked after application of topical brightly stain with fluorescein are typical of herpes simplex anesthetics. An acutely decreased visual acuity should raise a virus (HSV).19 Small, non-staining vesicles may be the only high suspicion for a vision-threatening process, such as AACG finding during the first 24 hours of HSV infection, or in or endophthalmitis. patients who are immunocompromised.19 Highly branched Western Journal of Emergency Medicine 510 Volume 18, NO. 3: April 2017 Gilani et al. Differentiating Causes of Acute Red Eye for the EP lesions without end bulbs are typical of varicella zoster virus (VZV), and these stain less