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CONJUNCTIVAL ABRASION, LACERATION, AND FOREIGN BODY
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The conjunctiva has less innervation than the cornea, so conjunctival abrasions are far less symptomatic than corneal abrasions. The patient may complain of a scratchy foreign body sensation, mild pain, tearing, and, rarely, photophobia. Vision should not be affected unless there is a full-thickness conjunctival laceration with globe penetration. Physical examination may reveal mild conjunctival injection or subconjunctival hemorrhage. A conjunctival abrasion is seen with fluorescein staining.
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Conjunctival lacerations may bleed, the edges of the bulbar conjunctiva may retract with underlying sclera visible to the naked eye, and fluorescein stain may pool in the defect. Perform the Seidel test to exclude globe perforation. The Seidel test can be negative if a full-thickness laceration is small or has spontaneously closed. Inspect the conjunctiva for a foreign body. Conjunctival foreign bodies usually can be removed with a moistened, cotton-tipped applicator after anesthetizing the eye with a topical anesthetic. Evert the upper eyelid and inspect under the highest magnification available to avoid missing any additional foreign bodies. Frequently, small wooden particles such as sawdust will blend into the conjunctiva when moistened by the tears and be difficult to find without slit lamp magnification.
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Superficial conjunctival abrasions and lacerations without any other associated ocular injury only require erythromycin ophthalmic ointment 0.5% four times a day for 2 to 3 days or no treatment if very small. Suturing of lacerations is almost never required. Any suspicion of globe laceration requires immediate ophthalmologic referral.
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CORNEAL ABRASION, LACERATION, AND FOREIGN BODY
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The corneal epithelium is fragile and easily damaged. It is richly innervated and therefore very painful when injury occurs. Corneal epithelium regenerates quickly, so healing time for abrasions is short, usually within 24 to 48 hours. Intact corneal epithelium is resistant to infection, but damaged epithelium is a portal of entry for bacteria, viruses, and fungi. Most abrasions not treated immediately will develop an associated inflammatory iritis.
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Abrasions may be caused by contact lens wear, fingernails, makeup brushes, and foreign objects blown into eyes while driving or on windy days or that drop into the eye while working overhead (construction) or under a car (mechanics). Injury to the cornea causes intense pain that may be delayed several hours after the inciting event. Initial symptoms are a foreign body sensation, photophobia, and tearing. Ask about the work environment and the mechanism of injury if known, because corneal abrasions sustained using high-speed machinery, such as grinders, lawn mowers, or weed whackers, and hammering metal against metal are associated with corneal laceration and perforation of the globe.
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Inspection of the eye may reveal conjunctival injection, tearing, and lid swelling. Blepharospasm may occur with severe pain, requiring a topical anesthetic to accomplish the examination and obtain the visual acuity. Relief of pain with topical anesthesia is virtually diagnostic of corneal abrasion. Photophobia may be evident when shining a light into the affected or the opposite eye. Decreased visual acuity may occur if the abrasion is in the central visual axis or if there is an associated iritis, but otherwise vision should be normal. The corneal abrasion is often visible to the naked eye as an irregular area of light reflection off the cornea.
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Slit lamp examination may show flare and cells from iritis if the abrasion is large and >24 hours old, but there is no corneal infiltrate. Examine the entire thickness of the cornea for full-thickness laceration, and the Seidel test should be negative. The abrasion usually appears as a superficial, irregular corneal defect appearing bright green under the cobalt blue light after instillation of fluorescein (Figure 241-33). A series of small, fine-lined vertical corneal abrasions seen with fluorescein staining suggests the presence of a foreign body embedded in the tarsal conjunctiva of the upper lid. Multiple linear corneal abrasions or punctuate keratitis also suggest a retained foreign body under the upper lid.
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Some slit lamps (Haag-Streit) have a measuring dial attached to the mechanism that varies the length of the slit beam. If your slit lamp is equipped with this feature, you can vary the length of the slit beam on the cornea until it corresponds to the length or width of the abrasion. The reading on the wheel equals the length of the slit beam in millimeters. This additional feature allows you to document the dimensions of the abrasion precisely, thereby enabling subsequent examiners to evaluate the wound's healing response objectively.
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Because the majority of corneal abrasions heal spontaneously, treatment is aimed at relieving pain and preventing infection. Cycloplegics relax the ciliary body and relieve pain from spasm as well as decreasing secondary iritis. Patching the eye does not promote healing, but some patients feel better with the eye patched. Loss of depth perception results from patching one eye, so patients should not drive a car. Abrasions from fingernails, vegeTable matter, or a contact lens should not be patched, as they are at higher risk of infection.
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If an abrasion is >2 mm or very painful, prescribe a cycloplegic agent (cyclopentolate 1% or homatropine 5%), one drop three to four times a day at home, to help control discomfort. The duration of action for each agent is much shorter in the inflamed eye, so a several times a day dosing schedule is recommended. Cyclopentolate 1%, one drop three times daily, wears off within 24 hours. Homatropine should be reserved for very large, painful abrasions and lasts several days. Avoid atropine because the effect lasts for approximately 2 weeks. Topical nonsteroidal anti-inflammatory drugs such as ketorolac and diclofenac give some degree of pain relief and do not impair healing in patients with corneal abrasions. Topical antibiotics can be provided (Table 241-7).
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Large abrasions or abrasions in the central visual axis should be checked by an ophthalmologist in 24 hours; small abrasions should be checked in 48 to 72 hours. Never prescribe topical anesthetics, as they inhibit corneal healing and obliterate the normal corneal protective mechanism (blinking when material gets into the eye).
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Applying an Eye Patch
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An eye patch may be preferred for comfort for some patients with corneal abrasions or may be needed to prevent keratitis in a patient with Bell's palsy. When an eye patch is properly applied, the eyelid will not move under the eye patch. Assemble supplies—two cotton oval eye pads and multiple pieces of tape pretorn to approximately 5 in. (13 cm). To properly apply an eye patch, have the patient sit with both eyes closed. Have the patient keep both eyes closed until the patch is applied and secure. Take one cotton oval eye pad, fold it in half, and hold the eye pad gently but firmly over the closed lid of the eye to be patched. Then take another eye patch, do not fold it in half, and place it over the first patch. Very deep set eyes may require a third patch. Keep holding firmly but gently. Then tape the patch in place, applying the tape in an X-fashion over the eye pad. Now have the patient open his or her eyes. If the patch is properly placed and taped, the lid under the patch will remain closed. If the patient says the lid can open, remove the patch and try again.
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Full-thickness corneal lacerations can be identified by a misshapen iris, macro- or microhyphema, decrease in visual acuity, and shallow anterior chamber. The Seidel test should be positive. However, small corneal lacerations can close spontaneously, the Seidel test will be negative, and there may be no gross distortion of globe anatomy (see Figure 241-48). Corneal lacerations occur in young children from a wide variety of objects—sharp sticks, fingernails, thorns, broken glass, or sharp toys.2 Objects as diverse as bungee cords and eyelash curlers3,4 can cause globe perforation. A history of eye irritation while working with metal fragments or high-speed machinery suggests the possibility of a corneal laceration. Pain out of proportion to physical findings, decrease in visual acuity, or other unexplained ocular symptoms may be the only symptoms or signs of a small full-thickness corneal laceration. Evaluate the entire thickness of the cornea during slit lamp examination to identify a corneal laceration.
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If there is any suspicion of penetrating injury, obtain a CT of the orbit to identify changes in globe anatomy or contour or a foreign body within the globe, and consult ophthalmology. The sensitivity of CT for the detection of occult globe perforation is reported as 56% to 68%,5 further emphasizing the need for a high index of suspicion. Unrecognized corneal lacerations can quickly result in endophthalmitis or traumatic cataract. Once endophthalmitis develops, vision is at great risk.
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Corneal Foreign Bodies
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Corneal foreign bodies are usually superficial and benign, but penetration of a foreign body into the globe can cause loss of vision. Foreign bodies are generally small pieces of metal, wood, or plastic that become embedded in the cornea. The presence of a corneal foreign body causes an inflammatory reaction, dilating blood vessels of the conjunctiva and causing edema of the lids, conjunctiva, and cornea. When the foreign body is present for >24 hours, WBCs may migrate into the cornea and anterior chamber as a sign of iritis.
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The patient will usually complain of a "foreign body" sensation during blinking. Tearing, blurred vision, and photophobia are common. Ask about details surrounding the onset of symptoms, including patient activity. If a cause is not obvious, ask about all activities in the previous 24 hours, especially activities that cause high-velocity projectiles. High-velocity globe penetration injuries include grinding, hammering metal on metal, or operation of other high-speed machinery. Visual acuity should be normal. Inspection of the eye may reveal edema of the eyelid and diffuse or focal/perilimbal conjunctival injection.
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Occasionally, the foreign body may be visible with the naked eye. Evert the lid to identify and remove other foreign bodies that may be present. When a metallic foreign body is present for more than a few hours, a rust ring (Figure 241-34) develops around the metal. Foreign bodies present for >24 hours may be surrounded by a white ring representing a WBC infiltrate. Anterior chamber flare and cells and a corneal foreign body are identifiable on slit lamp examination (Figure 241-35). The presence of a gross hyphema or a microhyphema evident in the anterior chamber on slit lamp examination suggests globe perforation. If the foreign body has penetrated the cornea, the tract of the projectile may be seen. The Seidel test may be positive with penetration of the globe.
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Corneal Foreign Body Removal Corneal foreign bodies should be removed carefully, with the patient and physician seated at each other's eye level, and under the best magnification available. Anesthetize the cornea with a local anesthetic such as 0.5% proparacaine. Sometimes, anesthetizing both eyes is helpful, because that can eliminate reflex blinking during attempts at foreign body removal. Irrigate with normal saline first, as a very superficial foreign body may be irrigated off the cornea. Next, try to dislodge the foreign body with a moistened cotton applicator. Efforts at removal may themselves cause corneal abrasion.
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If the foreign body is tightly adherent to or embedded in the cornea, inspect the cornea using optical sectioning to assess the depth of penetration (Figure 241-12). Full-thickness corneal foreign bodies should be removed by an ophthalmologist.
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For superficial foreign bodies, a 25-gauge needle (using needle bevel up) or a sterile foreign body spud (1 mm diameter) on an Alger brush (a low-speed, low-torque, battery-operated hand-held drill) can be used to remove the foreign body. Use slit lamp magnification to ensure safe foreign body removal. Before the removal, prepare a moistened cotton applicator and set it aside on the slit lamp table. The upper lid can be held open by an assistant or by the clinician's nondominant hand. Many slit lamps have an attached "fixation light" that can be moved in front of the unaffected eye to give the patient a steady target to concentrate on. Using either the 25-gauge needle or the Alger brush, place the tip into the slit lamp beam using the naked eye. With the tip close to the cornea, look through the slit lamp and move the tip into contact with the cornea. Using the bevel-up edge of the tip of the 25-gauge needle, hook the edge of the foreign body and dislodge it. You may then lift it off the cornea using the previously moistened cotton applicator. Alternatively, using the spinning tip of the Alger brush, the foreign body may be dislodged and removed with the cotton applicator as above.
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After successful foreign body removal, discharge the patient with a prescription for topical antibiotics, cycloplegics, and oral analgesics. Administer tetanus toxoid as appropriate. Provide ophthalmology follow-up the next day if the foreign body is in the central visual axis or if there is a residual rust ring. Otherwise, after complete removal of the foreign body, advise follow-up if symptoms persist at 48 hours.
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Rust Ring Removal Metallic foreign bodies can create rust rings that are toxic to the corneal tissue (Figure 241-34). If a rust ring is present, the spud or an ophthalmic burr can remove superficial rust, but rust often reaccumulates by the next day, requiring additional burring. It is therefore not necessary to remove a rust ring in the ED if the patient can be seen by an ophthalmologist the next day. Once the metallic foreign body is removed, the rust ring area softens overnight and can be more easily removed in the office the next day. The deeper the stromal involvement, the higher is the risk of corneal scarring, so if rust ring removal is done in the ED, only perform superficial burring. No ED drill burring should take place if the rust ring is located in the visual axis (pupil) owing to the risk of causing visually significant scarring. Such conditions require that an ophthalmologist remove the stromal rust in the office within 24 hours.
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Eyelid lacerations that involve the lid margin, those within 6 to 8 mm of the medial canthus or involving the lacrimal duct or sac, those involving the inner surface of the lid, wounds associated with ptosis, and those involving the tarsal plate or levator palpebrae muscle need repair by an oculoplastic specialist. Lacerations medial to the lacrimal puncta are at high risk of canalicular involvement. Suspect involvement of the levator palpebral muscle in the presence of a horizontal laceration with ptosis or when orbital fat is seen protruding through the laceration, indicating a breach of the orbital septum.
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Consider the possibility of corneal laceration and globe rupture in all full-thickness lid lacerations. Ocular injuries such as corneal abrasion, traumatic hyphema, and globe rupture are seen with lid lacerations in up to two thirds of cases. Lid lacerations require a thorough examination using a slit lamp to exclude other associated ocular injuries.
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Deep lacerations medial to the punctum potentially can transect the canalicular system. These injuries need to be seen by an ophthalmologist for evaluation of the nasolacrimal duct system's integrity. Instillation of fluorescein dye in the eye with subsequent appearance in the wound indicates loss of canalicular integrity. If a canalicular laceration is discovered, the patient will need to go to the operating room within 24 to 36 hours for repair and Silastic® tube stenting. Because a meticulous repair by an experienced eye surgery team is preferable, it is not unreasonable for the ophthalmologist to discharge a patient seen late in the evening or on the weekend with arrangements for surgical repair to take place within the next 36 hours. Patients discharged pending repair should be placed on oral and topical antibiotics and told to use cold compresses. Oral cephalexin (Keflex®), 500 milligrams twice or four times daily, and topical erythromycin ophthalmic ointment four times daily are reasonable choices.
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Partial-thickness lid lacerations not meeting the preceding criteria can usually be repaired in the ED, with referral for ophthalmologic evaluation in 2 to 3 days. Use a soft, absorbable or nonabsorbable 6-0 or 7-0 suture. Have the suture ends closest to the cornea tucked under more distant sutures to avoid corneal irritation (Figure 241-36). Cut the ends of each suture 1 cm long. When the second suture is tied, take the long ends of the first suture into the loop of the knot of the second suture. This keeps the ends of the first suture secure. Do this for every successive suture. Do not incorporate the ends of the suture into the wound itself, but make sure the suture ends are kept to the side of the wound margin. Sutures are removed from the bottom.
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Lacerations at the Lid Margin
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Very small lacerations (<1 mm) at the lid edge only do not need suturing and can heal spontaneously. Any laceration >1 mm at the lid edge needs repair by a specialist. Proper alignment of the lid margin during repair under magnification (loupe or microscope) is essential to preserve proper lid function and even corneal wetting with each blink. Notching of the lid can result in improper lid closure.
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If there is no opportunity for the patient to see an ophthalmologist, repair should be performed as in Figure 241-37. Soft (gut or chromic) sutures 6-0 or smaller should be used for all repairs. One vertical mattress suture, using the meibomian gland orifices as a landmark, or two 6-0 soft sutures (one approximating the anterior and the other the posterior lamella) are used to repair the lid margin. The initial suture can be used for traction to extend the lid and facilitate the repair. The tarsus should be repaired with 6-0 absorbable suture (polyglactin) from the external side so as to approximate the wound without the need for sutures on the conjunctival side of the lid (which would abrade the cornea with each blink). Skin closure can be performed with 6-0 or smaller soft nonabsorbable suture.
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The first steps are assessment of the visual acuity, anterior chamber, and integrity of the globe. The eyelids frequently swell shut, making visualization of the globe difficult. Prying the eyelids open with the fingers is difficult, usually yields an unsatisfactory view of the globe, and can raise intraocular pressure. Insertion of a paperclip bent in an appropriate shape (Figure 241-38) or an eyelid speculum (Figure 241-39) provides a significantly improved view of the cornea and anterior chamber. Use of an eyelid retractor allows your hands to remain free for examination of the globe using the slit lamp.
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If the anterior chamber is flat, a ruptured globe is certain, so stop the examination, place a metal shield over the injured eye, and consult ophthalmology. A hyphema is also evidence of significant ocular trauma and necessitates an ophthalmology consult. If the globe appears intact and vision is preserved, check ocular motility. Restricted upgaze or lateral gaze suggests a blow-out fracture with entrapment (see later section, Orbital Blow-Out Fractures), and a CT scan of facial bones should be obtained. A head CT scan may be indicated to assess for associated intracranial injury. Feel the orbital rim above and below for step-off deformities. Test for cutaneous sensation along the distribution of the inferior orbital nerve (below the eye and ipsilateral side of the nose). Perform a slit lamp examination with fluorescein staining to check for abrasions, lacerations, foreign bodies, hyphema, iritis, and lens dislocation. Measure intraocular pressure if there are no signs of a ruptured globe. Traumatic iritis is common, causing cell and flare to be seen on slit lamp examination. The pupil can be constricted or dilated after sustaining trauma. It is important to look for pupillary irregularity because the pupil often will peak toward the site of a penetration or rupture. If the anterior chamber is of normal depth and not shallow, apply a mydriatic. Nonwhite, brown-eyed individuals frequently will require an additional drop of a mydriatic to achieve adequate dilation. If vision and ocular anatomy and function are preserved, outpatient follow-up by an ophthalmologist in the next 48 hours should be planned. If a ruptured globe is suspected due to loss of visual acuity, flat anterior chamber, obvious full-thickness laceration, or intraocular foreign body, do not manipulate the eye or measure intraocular pressure. Consult ophthalmology immediately.
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A hyphema is blood or blood clots in the anterior chamber (Figure 241-15 and 241-16). Hyphemas are traumatic or spontaneous. A traumatic hyphema usually results from bleeding from a ruptured iris root vessel. Spontaneous hyphemas frequently are associated with sickle cell disease. In addition to standard ophthalmologic history, inquire as to the use of any anticoagulant or antiplatelet medications or history of a bleeding diathesis. A hyphema may layer out posteriorly when the patient is lying flat and may only become grossly evident when the patient is sitting upright. The complications of hyphema include increased intraocular pressure, rebleeding, peripheral anterior synechiae, corneal staining, optic atrophy, and accommodative impairment. Patients with large hyphemas, sickle cell disease, and bleeding tendency are more likely to develop vision loss. A microhyphema is suspension of red blood cells in the anterior chamber without the formation of a layered blood clot. It is generally seen with a slit lamp and can progress into a hyphema. The most significant complications of microhyphema include rebleeding and intraocular pressure elevation. Patients with sickle cell disease are more likely to develop these complications. The treatment of microhyphema is somewhat controversial, but the principles of management are the same as those for the hyphema.
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Hyphemas should be evaluated by an ophthalmologist in the ED. Patients at high risk for complications include those with suspected ruptured globe, those with sickle cell disease, those taking anticoagulants, or those with a bleeding diathesis.
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Treatment consists of the prevention of rebleeding and intraocular hypertension. Elevate the patient's head to 45 degrees to promote settling of suspended red blood cells inferiorly to prevent occlusion of the trabecular meshwork. After consultation with the ophthalmologist, dilate the pupil to avoid "pupillary play" (constriction and dilation movements of the iris in response to changing lighting conditions), which can stretch the involved iris vessel, causing additional bleeding. Pupillary dilation does not compromise the angle and aqueous outflow in normal individuals, and some ophthalmologists choose to dilate hyphemas to prevent pupillary activity. Control of intraocular pressure consists of topical β-blockers, IV mannitol, topical α-adrenergic agonists (apraclonidine), and oral, topical, or IV carbonic anhydrase inhibitors such as Diamox®. Do not give carbonic anhydrase inhibitors to patients with sickle cell disease. Carbonic anhydrase inhibitors lower the aqueous pH in the anterior chamber, causing the red blood cells to sickle and become less flexible, thereby clogging outflow through the trabecular meshwork and increasing intraocular pressure.
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Rebleeding can occur 3 to 5 days later in up to 30% of cases, sometimes causing severe elevation of intraocular pressure and necessitating surgical anterior chamber "washouts." Because of this risk, some ophthalmologists believe in admitting all patients with hyphemas, whereas others will choose to follow them closely as outpatients. Generally, patients with hyphemas occupying one third or less of the anterior chamber can be followed closely as outpatients. The disposition decision should be made by the ophthalmologist after examining the patient. Lower risk of rebleeding has been reported in patients who receive topical glucocorticoids. Additionally, topical steroids may prevent posterior synechiae and treat iridocyclitis. Close follow-up and serial examinations by an ophthalmologist are recommended in patients receiving topical ocular steroids to ensure no infection or corneal perforation occurs.
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Orbital Blow-Out Fractures
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The most frequent sites of orbital blow-out fractures are the inferior wall (maxillary sinus) and medial wall (ethmoid sinus through the lamina papyracea). Fractures of the medial wall can be associated with subcutaneous emphysema, sometimes exacerbated by sneezing or blowing the nose. Fractures of the inferior wall with entrapment of the inferior rectus muscle can cause restriction of upgaze and diplopia (Figure 241-40). Orbital wall fractures are suspected on clinical examination and confirmed by CT scanning. About one third of blow-out fractures are associated with ocular trauma (abrasion, traumatic iritis, hyphema, lens dislocation/subluxation, retinal tear, or detachment); therefore, a careful eye examination in the ED is necessary. All blow-out fractures with normal initial eye examination in the ED should be referred to an ophthalmologist for an outpatient fully dilated examination to rule out any unidentified retinal tears or detachments. Orbital blow-out fractures without any evidence of serious eye injury do not require admission.
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Isolated blow-out fractures with or without entrapment and without any eye injury do not require immediate surgery and can be referred to ophthalmology, plastic surgery, oral maxillofacial surgery, or otolaryngology (depending on the local referral patterns) for repair within the next 3 to 10 days. Oral antibiotics (cephalexin, 250 to 500 milligrams PO four times daily for 10 days) are often recommended because of the presence of sinus wall fractures.
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Rupture of the globe is a vision-threatening emergency that may be easily missed. The patient will usually complain of eye pain but may not have a decrease in visual acuity. Rupture of the globe presenting with a large subconjunctival hemorrhage is easily recognized, but a penetrating wound of the cornea caused by a tiny piece of metal launched from a grinder may be easily overlooked and requires a high index of suspicion to detect. Periorbital ecchymosis and maxillofacial fractures, including blow-out fracture with limitation of extraocular muscle movement, should raise one's suspicion for globe rupture.
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Scleral rupture may occur from blunt or penetrating trauma. Blunt trauma directly to the eyeball (for example, a blow by a fist) will cause a sudden elevation of intraocular pressure, with the globe tending to rupture at the thinnest points of the sclera, the limbus, and at the insertion of the extraocular muscles. Any object that impacts the orbital rim at a high velocity and causes a seal around the orbit (tennis balls, racquetballs, etc.) will also cause a sudden peak in intraocular pressure and may result in rupture. A history of ocular surgery or previous ocular injury may predispose to globe rupture. Penetrating trauma may occur from bullets, BB pellets, knives, sticks, darts, needles, hammering, and lawn mower projectiles. Any projectile injury has the potential for penetrating the eye. The bony canal protects the globe from posterior and oblique injuries, but the eyelids afford little protection anteriorly. Suspect globe penetration with any puncture or laceration of the eyelid or periorbital area, and make sure to conduct a thorough slit lamp examination. The smaller the diameter of the offending object, the higher is the likelihood of occult injury. Corneal abrasions occurring when hammering metal on metal; associated with the use of high-speed machinery such as lawn mowers, line trimmers (weed whackers), grinders, or drills; and sustained during explosions should always be investigated for occult globe penetration.
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Whenever globe rupture is obvious or strongly suspected, cover the eye with a metal eye shield or make a shield from a paper cup (Figures 241-41 and 241-42), and consult ophthalmology immediately without further manipulation. Elevate the head of the bed to 45 degrees. Administer broad-spectrum IV antibiotics, and give tetanus toxoid as appropriate. Provide sedation and analgesia, and administer antiemetics to prevent increased intraocular pressure and extrusion of intraocular contents from vomiting. Avoid any topical eye solutions. Give the patient nothing by mouth, anticipating surgery.
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Most cases, however, will require an initial eye examination to determine the type and extent of injury before consulting ophthalmology. If at any step of the examination globe rupture is suspected, stop the examination, place a protective shield over the eye, and consult ophthalmology. Do not measure intraocular pressure as this may result in extrusion of globe contents.
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Eye examination must be careful and gentle. Manufactured or homemade eyelid retractors should be used to gently retract the lids to examine the eye and to avoid increasing intraocular pressure during examination.
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Examination of the eye may reveal decreased visual acuity, an irregular or teardrop-shaped pupil, an afferent pupillary defect, shallow anterior chamber, hyphema, positive Seidel test, and lens dislocation (Figure 241-43). Presence of a large subconjunctival hemorrhage involving the entire sclera or hemorrhagic chemosis (bullous, raised subconjunctival hemorrhage) is very suspicious for rupture of the globe (Figure 241-44 and 241-45). Uveal prolapse through a scleral wound may appear as a brownish-black discoloration against the white sclera (Figure 241-46). One may occasionally visualize a corneal laceration (Figure 241-47) or an intraocular foreign body on slit lamp examination (Figure 241-48). The Seidel test may or may not be positive with a small corneal laceration. Funduscopic examination may reveal a poor view of the optic nerve and posterior pole due to vitreous hemorrhage. Unfortunately, the examination may be nearly normal after globe rupture from a tiny high-speed projectile.
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The diagnosis is made based on a combination of history, physical examination, and selected radiologic studies. CT scan of the eye is the preferred imaging modality to detect occult open globe rupture and associated optic nerve injury. CT scan of the orbit using 2- to 3-mm cuts in both the axial and coronal planes will also localize small intraocular foreign bodies. US and both direct and indirect ophthalmoscopy after pupillary dilatation may assist in the diagnosis and can be helpful in locating and confirming the presence of orbital and intraocular foreign bodies. MRI is contraindicated if a metallic foreign body is possible.
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For patients in the ED with multiple trauma and a possible ruptured globe who require rapid-sequence intubation, there is no clear consensus on the best agent to use because quick airway stabilization takes priority. Although a depolarizing agent like succinylcholine is associated with an increase in intraocular pressure, the underlying mechanism is not clear. Some studies suggest that intraocular pressure increases because of extraocular muscle contraction, although others suggest it increases because succinylcholine has a cycloplegic effect on the ciliary muscle. Pretreatment with a nondepolarizing muscle relaxant or a pretreatment dose of succinylcholine does not necessarily attenuate the increase in intracranial pressure. Use of a nondepolarizing agent like rocuronium can mitigate increases in intraocular pressure, but disadvantages are a longer onset and longer duration of action6 (see Chapter 29, Intubation and Mechanical Ventilation).
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Orbital Hemorrhage: Preseptal and Postseptal
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Severe blunt trauma to the orbit can occasionally cause an orbital hemorrhage. Preseptal hemorrhage is dramatic in appearance, but not as vision threatening as a postseptal hemorrhage (often called retrobulbar hematoma), which can cause an orbital compartment syndrome. A postseptal hematoma can cause an abrupt increase in intraocular pressure, resulting in decreased blood flow to the optic nerve and its blood supply and loss of vision.
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Traumatic periorbital hematomas (black eyes) are common, but the extension of bleeding into the postseptal compartment is a true emergency. Differentiation of preseptal versus postseptal hematoma depends on the examination and noncontrast orbital CT findings. Clinical findings of postseptal hemorrhage are eye pain, proptosis, impaired extraocular movements, decreased vision, possibly an afferent pupillary defect, and elevated intraocular pressure. An intraocular pressure >40 mm Hg is a consideration for emergency lateral canthotomy. No matter what the intraocular pressure, if postseptal hematoma is suspected or confirmed, request emergency ophthalmology consultation. Preseptal hematomas can be observed to make sure that the hematoma is not expanding.
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The goals of lateral canthotomy are to release pressure on the globe and to reduce intraocular pressure to reestablish retinal artery blood flow. To perform the procedure, place the patient in the supine position and anesthetize the lateral canthus area with 1% to 2% lidocaine with epinephrine. Place a straight Kelly clamp horizontally across the lateral canthus for about 1 to 2 minutes to crush the tissues and minimize bleeding. Remove the clamp, and with sterile scissors, make a 1- to 2-cm lateral incision in the compressed tissue at the clamp site. Then retract the lower lid to expose the lateral canthus tendon. With the scissors directed inferoposteriorly toward the lateral orbital rim, cut the inferior crus of the lateral canthus tendon. This critical incision is generally 1 to 2 cm in depth and length. If the procedure is successful, the intraocular pressure should be less than 40 mm Hg and the visual acuity should improve. If the intraocular pressure continues to remain elevated, the superior crus of the lateral canthus tendon can be cut in a similar fashion. The complications of lateral canthotomy include hemorrhage, infection, and mechanical injury. These complications generally respond to treatment better than does retinal injury from prolonged ischemia. Lateral canthotomy incisions usually heal well without suturing or significant scar formation.
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Ocular Hemorrhage and Antithrombotic Therapy
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The use of anticoagulant and antiplatelet agents is very common in current clinical practice and can complicate the management of ocular hemorrhage from trauma. Spontaneous ocular hemorrhage has also been reported in patients taking these agents. Ocular complications in patients on oral anticoagulant therapy include subconjunctival hemorrhage, hyphema, vitreous hemorrhage, subretinal hemorrhage, and choroidal hemorrhage. A higher incidence of hemorrhagic complications has been reported in patients with macular degeneration using anticoagulants or other antithrombotic drugs. Ocular hemorrhages in patients taking warfarin can potentially be vision-threatening events, but frequently they are benign and resolve without any sequelae.
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There are no clear guidelines to guide treatment of ocular hemorrhage in patients taking anticoagulant and antiplatelet therapy. The severity of bleeding, INR levels, and benefits of using these agents should be taken into consideration when managing these patients. Ophthalmologic and hematology consultations should be obtained. These medications should be stopped in patients with active bleeding. Prothrombin complex concentrate, fresh frozen plasma, and vitamin K should be considered in patients taking warfarin (see chapter 239 for detailed discussion). Platelet transfusions might be beneficial to stop active bleeding in patients with thrombocytopenia or taking antiplatelet drugs. Currently, no specific reversal agent for dabigatran is available. Activated prothrombin complex concentrates, recombinant factor VIIa, or concentrates of coagulation factors II, IX, or X and dialysis should be considered in patients taking dabigatran with active hemorrhage.
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CHEMICAL OCULAR INJURY
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Chemical burns to the eye are a true ocular emergency. Complications of chemical burns to the eye include scarring of the cornea with permanent loss of vision and loss of the eye due to corneal perforation. Irrigation of the eyes with 1 to 2 L of normal saline must be done immediately and before any examination, including testing of vision.
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Alkali and Acid Injuries
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Alkali injuries occur more frequently than acid injuries, due to the presence of alkaline substances in household cleaning agents and in building materials. The most serious alkali injuries are associated with ammonia, found in many household cleaners, and lye, a common ingredient in drain cleaners. Lye is also a component of concrete. Alkali injuries tend to be much more serious than acid injuries because they cause a liquefaction necrosis, characterized by denaturing of proteins and saponification of fats, allowing deep penetration into tissue. Acid, on the other hand, causes coagulation necrosis, with denaturing of protein forming a coagulum that acts as a barrier to further tissue penetration.
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Irrigation should begin at the scene and continue in the ED. Instill a topical anesthetic and continue irrigation for at least 30 minutes. Then check pH by touching a strip of litmus paper to the inferior conjunctival fornix. If the pH is >7.4, continue irrigation until the pH remains neutral 30 minutes after the last irrigation. Irrigation should be with sterile normal saline or other isotonic solution and may be instilled into the eye by hand, using bottles of eye-irrigating solution, or by a Morgan Lens® (MorTan Inc., Missoula, MT) (Figure 241-49) attached to a bag of an isotonic IV solution.
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After irrigation and maintainance of ocular pH >7.4, perform the eye examination. Inspect the facial skin and eyelids for burns. Evert the eyelids and remove any particulate matter with a cotton applicator.
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Exposure to chemical agents can cause conjunctival injection and chemosis, but severe chemical burns can cause scleral whitening, secondary to ischemia and blood vessel injury. Document visual acuity and measure intraocular pressure. Intraocular pressure may be increased if the trabecular meshwork has been damaged. Use the slit lamp to evaluate corneal injury and to detect for cells and flare in the anterior chamber. Injury to the cornea may range from punctuate defects to complete loss of epithelium. The cornea may become cloudy with severe burns (Figure 241-50).
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After irrigation, and once time permits, identify the substance. The pH is usually listed on bottles of household cleaners. The U.S. Occupational Health and Safety Administration requires the patient's workplace to maintain Material Data Safety Sheets, a list of all the physical properties, including pH, of chemicals used at the site. Data on the pH of known chemicals can also be obtained from a poison control center or from Poisindex®. Alkaline substances with pH <12 or acidic substances with pH >2 are thought not to cause serious injury, but duration of exposure can increase severity of injury. Circumstances surrounding the injury (e.g., battery explosion) should be determined to identify any other associated ocular or facial injuries.
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Obtain ophthalmology consultation for all but minor burns: Any patient with corneal clouding or an epithelial defect after irrigation should receive prompt ophthalmology referral.
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Patients with chemosis (edema of the bulbar conjunctiva overlying the white sclera) and no corneal or anterior chamber findings should be treated after irrigation with erythromycin ointment four times daily and referred for an ophthalmologic examination in 24 to 48 hours. These patients are considered to have "chemical conjunctivitis."
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A topical cycloplegic agent should be used three times daily for pain reduction if an epithelial defect is present. Avoid phenylephrine as a cycloplegic, as it will constrict blood vessels, causing further ischemia to the limbus. Apply erythromycin ophthalmic ointment four times daily to affected eyes. Administer tetanus toxoid as appropriate. Consider prescribing topical corticosteroids after consultation with an ophthalmologist to control inflammation.
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CYANOACRYLATE (SUPER GLUE/CRAZY GLUE)
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Accidental instillation of cyanoacrylate adhesives into the eye and adnexa can cause adherence of the lids and clumps of adhesive to form on the cornea. Medicinal-grade cyanoacrylates are occasionally used to seal corneal perforations and are not toxic to the cornea, so there is rarely permanent damage to the eye. The mechanical abrasive effect of hard, irregular glue aggregates rubbing against the cornea with eye movement and blinking may cause corneal abrasions. To remove crazy glue, instill generous amounts of erythromycin ointment onto the eye and on the surface of the eyelids to moisten, lubricate, and provide antibiotic coverage. Clumps of glue on the surface should begin to loosen. Remove only those pieces that are easily removable. Gentle traction may separate the lids. The glue will loosen and become easier to remove in a few days.
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Refer to an ophthalmologist within 24 hours for complete removal.