Common causes of eye injury include physical injury due to accidents, physical assault, sporting injuries (including air-gun, paint-gun, pellet-gun injuries), motor vehicle accidents (including airbag injuries), or exposure to toxic chemicals (eg, some cleaning products). Exposure to strong ultraviolet light, as from a welding arc or bright sunlight reflected off snow, can injure the cornea (see Superficial Punctate Keratitis). Injury may be to the eyeball (globe), surrounding soft tissues (including muscles, nerves, tendons), and/or bones of the orbit.
General evaluation for an eye injury should include the following:
Tests of visual acuity
Pupillary appearance and responses
Range of extraocular motion
Visual fields to confrontation
Location and depth of eyelid and conjunctival lacerations
Location of any foreign bodies
Depth of anterior chamber
Presence of anterior chamber or vitreous hemorrhage, cataract, or absence of a red reflex
Retinal examination
Intraocular pressure determination
Imaging studies as indicated
A red reflex is the normal reflection of light from the retina. It is best seen in patients with dilated pupils and in photographs—unless the "red eye reduction" function is chosen on the camera. Detailed examination of the sclera, anterior segment (cornea, conjunctiva, anterior chamber, ciliary body, iris), lens, and anterior vitreous is best done with a slit lamp (see Slit-lamp examination). Although direct ophthalmoscopy can be used to examine the lens and some of the posterior structures of the eye, indirect ophthalmoscopy, usually done by an ophthalmologist, provides a more detailed and binocular view of these structures. Indications for indirect ophthalmoscopy include clinical suspicion of vitreous abnormalities (eg, hemorrhage, foreign body) and retinal abnormalities; clinical suspicion may be based on symptoms, injury mechanism, absence of the red reflex, or retinal abnormalities visible with direct ophthalmoscopy.
A plain radiograph of the face does not adequately detect all orbital or periorbital foreign bodies. However, if done for other indications, a plain radiograph may show the presence of a foreign body, especially one composed of metal. In such cases, a CT or MRI is then performed to confirm the presence of a foreign body. CT or MRI are also performed to detect orbital fracture.
However, if there is a possibility that a metallic foreign body is present, MRI should not be used as the initial imaging modality. MRI can cause additional injury to the eye by inducing movement of any metallic foreign bodies in the magnetic field. A screening plain film should be used to definitively rule out a metallic foreign body in suspected cases if an MRI is necessary for diagnostic purposes.
In general, plain radiographs are not a helpful diagnostic tool for ocular and orbital pathology, with the exception of identifying metallic foreign bodies. CT of the orbits and skull base is highly diagnostic, is easily available, provides excellent images of bony anatomy, and takes less than 60 seconds to perform. CT is therefore the imaging of choice in cases of trauma or acute pathology that requires urgent intervention, such as orbital abscess. MRI provides far better detail than CT of the orbital apex and skull base, and specific sequences can be used for specific pathologic entities. However, MRI of the orbit takes approximately 45 minutes to perform, may not be readily available in an emergency situation, and may suffer from severe degradation artifacts in uncooperative or claustrophobic patients.
Use of eye guards, goggles, or special eyeglasses, such as those constructed of polycarbonate lenses in a wrap-around polyamide frame, is a simple precaution that greatly reduces the risk of injury.
(See also Retinal Detachment.)
