Patients present to the ED with visual disturbances that may be painful or painless and may include loss of visual acuity, field cuts, diplopia, and headache. A detailed history and complete ocular examination are essential to obtaining the correct diagnosis and offering expedited treatment and referral. This review discusses the differential diagnosis for patients experiencing abnormal vision from a nontraumatic or minimally traumatic etiology, and reviews diagnostic and treatment strategies from an evidence-based perspective, including point-of-care ocular ultrasound. Management of the needs of special populations, such as patients with sickle cell disease, HIV, and those with a ventriculoperitoneal shunt, is reviewed.
A 40-year-old woman is brought in to the ED by her husband, complaining of blurred vision and dizziness. She said she had visited an urgent care clinic last week with a new diagnosis of migraine headache. Her examination is remarkable for right eyelid ptosis, limited movement of the right eye to left gaze, and a right dilated pupil compared to the left. Her husband comments that his brother “had the same thing with his diabetes,” and asks you to check her sugar, but you think something else might be going on...
A nurse interrupts and tells you there is another patient in the room next door who has suddenly lost sight in both eyes, and the nurse wants to know whether she should call a stroke alert. You excuse yourself and step out to see a 21-year-old woman who is hyperventilating and screaming, “I can’t see! I can’t see!” You ponder the cause of her symptoms, and you note that her medications include alprazolam and sertraline. You wonder what the best way to confirm your suspected diagnosis would be...
Before you can respond, another nurse interjects and asks for pain medicine for the man in room 4 who has a red, painful eye that developed overnight. Your first suspicion is that it's a simple case of conjunctivitis, but the patient has intense pain when light is shined in the opposite eye. You wonder what else could be going on...
The presentation of a patient with a change in vision is common in the emergency department (ED), and potential diagnoses range from the minimally significant, to vision-threatening, or even life-threatening. Clinician experience, availability of equipment and technology, and time may all impact the care of these patients. This issue of Emergency Medicine Practice focuses on a symptom-based approach to the management of a variety of nontraumatic ocular conditions. Advances in emergency ocular ultrasound techniques and other technological advances can promote diagnostic certainty, help emergency clinicians communicate with consultants, and improve outcomes. For a review on managing traumatic eye conditions in the ED, see the November 2015 issue of Emergency Medicine Practice, “Ocular Injuries: New Strategies in Emergency Department Management”.
A literature search was conducted using Ovid MEDLINE®, requesting English language articles published since 2014 involving humans, and excluding case reports. A total of 271 full-text review articles were found. An additional search was performed using the Cochrane Database of Systematic Reviews and Database of Abstracts of Reviews of Effects (DARE). Further PubMed searches were carried out for primary studies on specific topics. Specialty guidelines were also searched and reviewed.
Overall, there is a lack of high-quality evidence for most of the therapies that are typically used in the ED for ocular complaints; specific treatment and diagnostic modalities with strong supportive evidence are highlighted. Pertinent guidelines from the American Academy of Ophthalmology are included. There are no clinical practice guidelines available from the American College of Emergency Physicians or the American Academy of Emergency Medicine for the care of ocular emergencies.
A review of the basic anatomy of the eye and the visual pathway is helpful in understanding visual pathology. (See Figure 1.) Light enters via the cornea, exits the anterior chamber through the pupil and refracts off the lens, traversing the vitreous humor to the retina. Photoreceptors generate signals; rods for dim-light vision and cones for color- and bright-light vision. The macula, in the center of the retina, contains the fovea, where there is the highest concentration of cones, making it responsible for the most precise vision. The visual signals exit along the optic nerve and travel to the optic chiasm, where the impulses decussate; ie, information from one side of the visual field is interpreted by the opposite side of the brain. The signals continue from the optic chiasm to the lateral geniculate bodies, and on to the occipital lobe via the optic radiations. Included in the pathway is the Edinger-Westphal nuclei, from which the extraocular movements of the eye, accommodation, pupillary dilatation, and convergence are affected.
The ocular media encompass the transparent substances such as the cornea, aqueous humor, lens, and vitreous humor. As a group, these parts of the eye permit refraction and image transmission to the retina. Inflammation or deposition of cells or protein will obscure vision.
Pathology of the cornea presents with pain, redness, tearing, and a foreign-body sensation. Corneal pain will typically resolve with a topical anesthetic, while pain from more serious causes (glaucoma, intraocular foreign body, etc) will not. Corneal pathology may arise from a variety of causes, including infection, minor trauma, autoimmune disease, foreign body, and exposures (both chemical and ultraviolet).
2. “She had a headache and said her vision was off, but I checked her pressures and they were OK. She said she was better with the pain medicine, so I discharged her.”
Consider temporal arteritis in patients who are aged > 50 years with headache and visual complaints. Order an ESR and CRP in these patients. Visual loss can be rapid and sudden, so a timely diagnosis is essential.
3. “He said he saw those floaters all the time! His vision was fine.”
Always consider retinal detachment with a complaint of flashing lights or increased visual floaters. Remember that visual acuity is preserved when the macula is spared. Check for field cuts and perform a fundoscopic examination. Consider ocular ultrasound to find retinal detachment.
7. “He said he had blurred vision, but he wasn’t very specific about it, and I didn’t think much of it. I can’t believe he had a brain mass!”
Make sure you translate the patient’s words into an accurate medical diagnosis. Just as “dizzy” can mean anything from vertigo to orthostasis, “blurred vision” can signify diplopia, decreased visual acuity, a field cut, and more.
Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of subjects. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.
To help the reader judge the strength of each reference, pertinent information about the study, such as the type of study and the number of patients in the study is included in bold type following the references, where available. In addition, the most informative references cited in this paper, as determined by the author, are highlighted.
Why to Use
The Snellen chart provides a portable and quick method to assess visual acuity.
When to Use
Use the Snellen chart to assess binocular and monocular visual acuity in cooperative patients.
Edmund Tsui, MD
Priya Patel, MD
The Snellen chart provided in the MDCalc app is in-tended as a convenient screener for visual acuity to be used on a mobile device and should not be used as a replacement for in-office testing. Evidence supporting the use of smartphone applications (apps) for Snellen visual acuity is limited, and currently no app has been found to be accurate to within at least 1 line of formal visual acuity testing; further validation is required.
There are 2 main charts used to test visual acuity: (1) Snellen charts, which use a geometric scale, and (2) logMAR charts, which use a logarithmic scale. While both have been widely studied, Snellen charts are used more often in clinical practice and logMAR charts are used more often in the context of research studies, given the ease of statistical analysis. Data from 11 different smartphone apps found that the accuracy of the apps was limited; none were within 1 line of the true Snellen visual acuity (Perera 2015). One study suggested that the visual acuity on smartphone apps may not be completely accurate, but the results are reproducible, allowing the app to track change from baseline (Phung 2016). There has been 1 study validating the use of smartphone-based charts in measuring visual acuity; however, this validation was application specific and more studies must be conducted to evaluate the true validity of these charts (Bastawrous 2015).
Herman Snellen, MD
Kelly O’Keefe, MD, FACEP; Sarah Temple, MD, FACEP
Ashley Norse, MD, FACEP; Jeremy Rose, MD, MPH, FRCPC
April 1, 2020
May 1, 2023
4 AMA PRA Category 1 Credits™, 4 ACEP Category I Credits, 4 AAFP Prescribed Credits, 4 AOA Category 2-A or 2-B Credits
Date of Original Release: April 1, 2020. Date of most recent review: March 10, 2020. Termination date: April 1, 2023.
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