EMS Management of Eye Injuries

Excerpt

In the United States (USA), approximately 7.5% of people suffer eye injuries at some point in their lifetime. Of those, 6.1% are left visually impaired, 6.9% are partially blind, and 0.6% are completely blind. This amounts to roughly 1.5 million, 1.7 million, and 147,000 individuals with permanent visual impairment, partial blindness, and complete blindness, respectively. Recent estimates report 2 to 2.4 million cases of ocular trauma each year, with hospitalization occurring in about 22% of cases.

The elderly population has the highest incidence of hospitalization for ophthalmic trauma. Males are predominantly injured, and the cause of injury varies with age. Elderly persons most commonly suffer from falls, whereas adolescents and younger adults are more often injured in motor vehicle collisions and assaults. Children experience increased accidental and sports-related injuries. Eye trauma is one of the most common and preventable etiologies of visual impairment and blindness; despite increased emphasis on protective eyewear in recent decades, prevalence is expected to increase with the aging population.

Lasting visual impairment or vision loss is detrimental to one's activities of daily living (e.g., finding items, driving, etc.) and quality of life, so it is crucial to be well-prepared not just in injury prevention but also in its management.

Ocular anatomy includes the periorbital tissues, globe, cornea, iris, ciliary body, lens, vitreous humor, retina, choroid, and optic nerve. The majority of traumatic ophthalmic injuries comprise hemorrhages, lacerations, perforations, foreign bodies, fractures, and burns of these structures, as well as their sequela.

Some are readily apparent on examination; others require advanced testing or imaging to be identified. Many eye injuries, even minor ones, will warrant some treatment, ranging from topical medications to invasive surgical intervention. When an injury occurs, it is essential to prevent further damage and obtain a timely assessment so that appropriate treatment is not delayed, as this may negatively and indelibly affect visual outcomes. This begins with the first point of contact with medical personnel, often Emergency Medical Services (EMS).

EMS may be dispatched to a wide range from isolated eye trauma to severe trauma with multiple injuries. During the latter, after any life threats have been addressed, it is essential to recognize an eye injury during the initial assessment, especially those which are threats to vision, so prompt action is taken by EMS and the receiving facility to provide the best outcomes for patients. A focus will be directed to open globe injury, orbital compartment syndrome, chemical injury, and corneal foreign body, as patients with these diagnoses, in particular, benefit the most from immediate awareness and action in the field.

History and Physical Examination

Essential historical information to gather includes location and timing of the injury, mechanism, and--in the instance of penetrating trauma or foreign body--the material. There are various eye-specific symptoms, such as vision change, double vision, floaters or shiners, discharge, photosensitivity, foreign body sensation, etc. Pertinent past medical history includes baseline visual acuity, contact lens use, and previous ophthalmological surgeries. A systematic examination ensures a complete assessment when possible.

This includes visual acuity and field testing, pupillary and extraocular muscle (EOM) exams, and, finally, visual inspection. The use of a Snellen eye chart may be excessive for the prehospital setting and deferred for the ED; however, a gross assessment of visual acuity can be performed by checking for the perception of light, detecting hand motion, and ability to count fingers and/or read print. Peripheral vision of all four quadrants must also be checked.

Pupillary examination entails direct reactivity to light and the swinging light test, which evaluates for a relative afferent pupillary defect (rAPD). In rAPD, When light is repeatedly swung from one eye to the other, the injured eye will constrict appropriately when the light is pointed at the contralateral eye but dilate when the light swings directly to it. In the setting of trauma, this can be suggestive of optic nerve injury, retinal detachment, or vitreous hemorrhage.

Extraocular muscle assessment is done by having the patient track in the six cardinal positions of gaze (i.e., right, left, and all four corners). Failure to do so with one eye or the presence of diplopia is suspicious for EOM injury. Most notably, failure of the eye to track superiorly is concerning for orbital floor fracture with EOM entrapment--an urgent surgical matter.

Regarding visual inspection, an external-to-internal process is a simple and easy approach to be thorough and avoid missing an injury. Begin with the periorbital soft tissue and eyelid before observing the general position of the globe. Anterior, posterior, or inferior displacement (exophthalmos, enophthalmos, and hypoglobus, respectively) raises concern for major injuries such as orbital fracture, retrobulbar hematoma, and optic neuropathy.

Inspection of the cornea, sclera, and iris may be performed next and may reveal a foreign body, penetrating eye injury, and traumatic hyphema (collection of blood in the anterior chamber), to name a few. Scleral or deep corneal lacerations, iris or pupillary abnormalities, or prolapse of the iris or uvea through a corneal laceration must prompt concern for open globe injury and management as further described below. Otherwise, a thorough investigation of every section of the eye and underside of the eyelids may be done to complete the assessment.