• Are contact lenses used? If so, what type, how are they cleaned, and how old are the lenses? Has there been a change in the pattern of use (especially increased use)? Were the lenses worn for a particularly long period recently? Are there problems with the lenses drying out? Does insertion of the lenses worsen or relieve the symptoms? Contact lenses alter the physiology of the cornea, making it relatively hypoxic, drier, and more susceptible to bacterial infection with subsequent ulceration.

• Are glasses worn? If so, when was the last assessment for adequate refraction? When the patient is examined for objective abnormalities in visual acuity, the patient’s subjective interpretation of changes from his or her baseline may be all that is available when corrective lenses are not available or their prescription is out of date.

• Has previous injury or eye surgery occurred? Abnormal examination findings, such as an eccentric or irregularly shaped pupil, may be the patient’s baseline. Pain and redness are expected shortly after eye surgery, but many surgical complications also manifest with a red and painful eye.

• What is the patient’s usual state of health? Several systemic diseases may cause symptoms and signs in and around the eye. Giant-cell arteritis is a vasculitis with subacute systemic manifestations but often acute eye complaints.

• What medications are being taken? Medications that affect the sympathetic or parasympathetic nervous systems may affect ocular physiology, such as aqueous production, or pupil size and reactivity. Bleeding may be potentiated by anticoagulant or antiplatelet medications.

• Are there any known or suspected allergies? Environmental allergens are a common cause of conjunctivitis. Other superficial manifestations can be from chemicals (e.g., contact lens-cleaning solution) or other materials (e.g., makeup).

Visual Acuity

The initial determination of a patient’s visual acuity provides a baseline from which deterioration or improvement may be followed. It is also predictive of functional outcome after ocular trauma. Visual acuity is quantitatively assessed by use of a Snellen chart test at a distance of 20 feet (6 m) or a Rosenbaum chart at a distance of 14 inches. Young patients who cannot yet read letters and numbers should be tested with an Allen chart that depicts easily recognizable shapes. Each eye is tested separately, with the opposite eye carefully covered. Patients who do not have their prescribed corrective lenses may be evaluated by having them view the chart through a pinhole eye cover, which negates most refractive errors in vision.

If the patient cannot distinguish letters or shapes on a chart, visual acuity is determined qualitatively. Any printed material suffices. The result may be recorded as, for example, “patient able to read newsprint at 3 feet.” If this is not possible, visual acuity is recorded as:

Visual Field Testing

Confrontation is the most common method of testing visual fields in the ED but is unreliable for detection of anything short of an extensive field deficit. Fortunately, visual field examination rarely adds useful information in the evaluation of the acutely red and painful eye. Detection of a scotoma usually represents a retinal problem. However, glaucoma may cause scotomata that can be crescent shaped, involve just the binasal visual fields, or affect all peripheral vision. Hemianopia or quadrantanopia is more commonly a problem of the neural pathways to the brain.

External Examination

Gross abnormalities are assessed by a visual inspection of both eyes simultaneously. Findings may be more apparent if compared with the opposite side. Fractures of facial bones are associated with ocular injuries, some of which require immediate intervention by an ophthalmologist.²

Globe position is part of the external examination. Subtle exophthalmos and enophthalmos are rare and are best detected by looking inferiorly, tangentially across the forehead, from over the patient’s scalp. Exophthalmos (proptosis) may have traumatic or nontraumatic causes but is a result of increased pressure or a space-occupying lesion within the orbit, which may manifest as pain. Medical causes include cellulitis or intraorbital or lacrimal tumors. Hyperthyroidism may cause enlargement of extraocular muscles. The most important cause of exophthalmos in the ED is retrobulbar hematoma, a condition characterized by hemorrhage within the bony orbit, behind the globe. Orbital compartment syndrome pushes the globe forward, stretching the optic nerve and retinal artery and increasing IOP. The resulting microvascular ischemia is sight-threatening if sufficiently severe and persistent. Orbital emphysema and inflammation caused by a retained foreign body behind the eye are other causes of exophthalmos. The discovery of exophthalmos should prompt ocular tonometry measurements to determine the urgency of intervention. Trauma, particularly penetrating globe injury with extrusion of vitreous, can cause the globe to recede into the orbit, but the most common cause of enophthalmos is actually pseudoenophthalmos when the contralateral globe is proptotic.

Inspection also involves examination of the upper and lower palpebral sulci for foreign bodies or other abnormalities. The lower sulcus is easily viewed after manual retraction of the lower lid toward the cheek and having the patient gaze upward. The upper sulcus is inspected by pulling its lashes directly forward and looking under the lid with white light. The lid can then be everted by pressing a cotton-tipped applicator in the external lid crease and folding the lid margin over the applicator.

Conjunctivitis is a common diagnosis after evaluation of patients with red and painful eyes, but determination of cause is much more difficult on clinical grounds. Patients may be unaware of exposures that could cause a chemical conjunctivitis. Without a known history of environmental allergies or other symptoms and signs to suggest an allergic reaction, allergic conjunctivitis may be mistaken for an infection. However, these are usually managed with removal of any known offending agent and symptomatic relief only. On the other hand, acute infectious conjunctivitis can be bacterial or viral, and management should ideally be directed toward the specific microbiologic cause. The acute management of infectious conjunctivitis accounts for over one-half billion dollars in indirect lost productivity and direct costs of antibiotic prescriptions,³ when many patients do not need them.⁴

The presence of punctate “follicles” (i.e., hypertrophy of lymphoid tissue in Bruch’s glands) along the conjunctival surfaces of one or both lower lids has been touted to be relatively specific for a nonbacterial (i.e., viral or toxic) cause—though one notable exception is trachoma, a chronic keratoconjunctivitis caused by Chlamydia trachomatis. Indeed, the “typical” viral “pinkeye” has been called acute follicular conjunctivitis.⁵ Some authorities also believe that the mucoid discharge associated with viral conjunctivitis can be clinically differentiated from the purulent discharge associated with bacterial infection.⁶ However, most research studying the association of symptoms and signs with positive bacterial cultures have grouped “mucoid or purulent” discharges into one finding, not requiring primary care physician participants to discriminate between the two during data collection.^7,8 Thus no experimental evidence supports or refutes these expert opinions.⁹

Eyelids sticking together, particularly in the morning, is commonly cited as clinical evidence of bacterial, as opposed to viral, conjunctivitis, but this is unreliable. One multicenter primary care study in the Netherlands used logistic regression analysis to conclude that its presence plus the absence of itch and a prior history of conjunctivitis was associated with bacterial conjunctivitis; however, the 95% confidence intervals for the area under the receiver operating characteristic curve ranged from 0.63 to 0.80, thus making it a poor to only fair clinical prediction rule.⁷ In a single U.S. pediatric ED spanning ages from 1 month to 18 years, a similar analysis found sticky eyelids and either mucoid or purulent discharge to have a positive likelihood ratio of 3.1, and a post-test probability of 96% for positive bacterial cultures in their population; however, this likelihood ratio also indicates only a poor-to-fair test.⁸ Viral cultures were not performed in either of these studies, so the possibilities of copathogens or bacterial culture of nonpathogenic flora was not assessed. Therefore no good evidence exists for differentiating bacterial from viral causes on clinical grounds.

Extraocular Muscle Function

Limitation of ocular movement in one eye may be detected by having the patient follow the examiner’s finger or a bright light through the cardinal movements of gaze. The eyes may move in a disconjugate fashion, or the patient may admit to diplopia if asked. Diplopia on extreme gaze in one direction may indicate entrapment of one of the extraocular muscles within a fracture site but more often is caused simply by edema or hemorrhage related to the injury and is functional rather than actual entrapment. In the absence of trauma, diplopia is rarely associated with redness or pain.

Pupillary Evaluation

The pupils are inspected for abnormalities of shape, size, and reactivity. These examinations are conducted with light specifically directed into the pupil and by means of the swinging flashlight test.

Blunt or penetrating trauma, previous surgery (e.g., iridotomy for cataract extraction), and synechiae from prior iritis or another inflammatory condition are the most common causes of irregularly shaped pupils.

Asymmetrically sized pupils may represent normal or pathologic conditions. Physiologic anisocoria is a slight difference in pupil size that occurs in up to 10% of the population. Topical or systemic medications, drugs, and toxins may cause abnormal pupillary constriction or dilation.

Pathologic reasons for failure of one pupil to constrict with a direct light stimulus include globe injury, abnormalities of afferent or efferent nerves, and paralysis of the ciliaris or sphincter pupillae muscles in the iris. Potentially serious problems that also cause pain and redness include uveitis and acute angle–closure glaucoma.

The swinging flashlight test is used to determine whether a relative afferent pupillary defect (RAPD) exists. The patient fixes the gaze on a distant object, and the examination room is darkened. The size of the pupils in lowered light is noted, and unless there is physiologic anisocoria, the pupils should be equal in size. The direct and consensual light responses of the eyes are compared as a light source, angled into the pupil from in front of the cheeks, is swung back and forth between the two. When the light source shines into an eye with an RAPD, the pupil dilates because the consensual response from withdrawal of light from the opposite eye with normal afferent activity is stronger than the direct constrictive response to light in the affected eye with inhibited afferent activity. It is termed “relative” because the response is compared with that of the opposite side as the light source is alternated between eyes. An RAPD may be partial or complete and may result from inhibition of light transmission to the retina because of vitreous hemorrhage, loss of some or all of the retinal surface for light contact because of ischemia or detachment, or the presence of lesions affecting the prechiasmal optic nerve (e.g., optic neuritis).