In the third segment of our summer series on eye injuries, we will focus on blunt trauma to the eye and surrounding structures. A blunt impact may damage the frontal portion of the eye (the eyelid, conjunctiva, sclera, cornea, iris, and lens), or the back portion (the retina and the optic nerve). Such an impact may also fracture the bones that surround the eye (the bony orbit) or cause lacerations to the tissues of the eye.
The "Black Eye”
In the first 24 hours after a blunt injury to the eye, the skin and surrounding tissues become bruised and swollen. This is typically referred to as a "black eye." This bruise around the eye results from blood leaking into the tissues surrounding the eye, which eventually drains to the lower orbit causing a rainbow of colors from black to green-yellow. These injuries, if unaccompanied by more severe injury, have no effect on vision and usually resolve within a few days to a week. During the first 24-48 hours, ice packs can be helpful to reduce pain and swelling. A black eye should always be evaluated in the office, especially if the eye is swollen shut, if there is severe pain, if there is any obvious bleeding, changes in vision, or if accompanied by other facial injuries.
A subconjunctival hemorrhage is bleeding that occurs within the thin layer of tissue that covers the surface of the eye. This typically happens when small vessels on the conjunctiva break and bleed after trauma. This may even occur after very minor trauma such as rubbing the eye. With these injuries the entire white area of the eye may appear red and patients are often quite alarmed. This condition is, however, very minor and requires no treatment if there are no associated injuries. The bleeding will generally resolve within one to two weeks. Subconjunctival hemorrhage often accompanies a black eye.
A hyphema is bleeding into the frontal chamber of the eye (the fluid-filled space between the clear cornea and the colored iris of the eye). If the hyphema is large, it may be visible to an observer as it settles into the lower portion of the eye, however, bleeding is usually small to microscopic and may not be obvious. A hyphema can potentially be a serious injury resulting in permanent, partial, or complete loss of vision. Patients with a hyphema will often have blurred vision, and pain when exposed to bright light. These patient will be treated aggressively by the ophthalmology department and will be seen in the office daily for three to five days. This is the window of time when re-bleeding may occur. Treatment of these patients involves bed rest with the head of the bed elevated and eye drops to dilate the pupil and decrease inflammation. Aspirin and NSAIDS (Ibuprofen, Naproxen) should be avoided in these injuries to decrease the risk of re-bleeding. Patients who have had a hyphema have an increased lifelong risk of developing glaucoma and should have yearly eye exams after this injury regardless of age.
Traumatic iritis often accompanies a hyphema as well as other blunt eye injuries and results in painful swelling and inflammation of the eye. These patients are acutely painful and sensitive to light and often the eye is quite injected (red). Treatment involves application of topical steroids to decrease inflammation and cycloplegic eye drops to dilate the pupil, essentially paralyzing the ciliary muscles to decrease spasm. Fortunately, this condition generally runs a benign course with complete resolution of symptoms within a week.
The retina is a light sensitive layer of tissue, which lies on the optic disc in the back of they. It contains photosensitive cells that convert light energy into signals, which are then carried to the brain via the optic nerve. Blunt trauma to the eye may cause part or the entire retina to detach or "tear" away from underlying optic disc. Usually these tears are partial but can progress if prompt treatment does not occur. Initially retinal detachment creates images of floating shapes (floaters) or flashes of light. Parts of the visual field may be blurred or completely absent. This is when a patient that needs immediate triage to the ophthalmologist who may be able to reattach the portion of torn retina, or stabilize the tear to prevent it from worsening through the use of surgery, lasers, or freezing.
Orbital Wall Fractures
The globe of the eye is protected by the helmet of the skull within the "bony orbit” (eye socket). However, the bony orbit walls are thin and tend to break with blunt impact to the eye. This is especially true of the orbital floor and the medial walls. The face is designed in such a way that an extra layer of protection is provided for the eye though the surrounding sinuses. With blunt trauma to the face and eye, the sinuses act as a crumple zone to diffuse the energy of a violent impact. When the eye is hit, the orbital contents break through and herniate into one of these sinuses. This posterior displacement of the eye prevents complete destruction of the globe. When this occurs, however, the muscles and/or contents of the eye can become entrapped in these fractures. These cases almost always require immediate surgery to release the entrapment and stabilize the fracture. With prompt treatment, the outlook for these patients is very good. Symptoms of orbital fractures with entrapment are changes in vision and color, decreased ability to move the eyes from side to side, crepitus or instability of the bones along the orbital (eye socket) rim. Numbness of the forehead and cheek indicates involvement of the facial nerves.
If you have any questions about eye health or eye injuries, please contact the occupational health department at firstname.lastname@example.org. Our September issue will be our last segment on eye injuries and will focus on lacerations of the eye and surrounding tissues and chemical and blood splashes/exposures.