Sudden IMPACT: Managing Acute Injuries
Sudden IMPACT: Managing Acute Injuries
An action plan for corneal trauma and other emergencies.
By Thomas John, MD
ILLUSTRATION BY BOB KAYGANICH/DEBORAH WOLFE, LTD
Traumatic ocular injury may be a “life-changer” for patients, taking them from sight to complete darkness within a matter of seconds. Bilateral globe rupture can be devastating for patients, and may be a subsequent burden on the immediate family and society in general. Other ocular injuries may not be quite so dramatic, but can still result in a much-diminished quality of life. Hence, successful treatment of such injuries is of paramount importance to mankind globally. Is your practice prepared, should an emergency walk through your door? Read on for a review of typical ocular injuries that may come into your office, as well as guidelines for their assessment and management.
Eye Trauma Stats
Unlike other organs in the human body, the eye is exposed to the environment and hence it may be violated by direct trauma, whether accidental or intentional. Ocular trauma may be viewed for the most part as a bi-channel globe injury; namely, blunt and penetrating ocular trauma, both of which may have differing types of ocular tissue damage depending on the amount of force, the type of object involved and the ocular site of impact. There is a third channel of injury as well — ocular burns, which may be thermal or chemical (acid and alkali).
Fortunately, a majority (76%) of ocular trauma cases are usually minor, with full recovery, and mild to moderate impairment in 17%.1 However, a smaller segment of the injured may sustain serious, sight-threatening ocular injuries; this group accounts for 7% of the legally or totally blind. In the US, more than 2.5 million sustain an eye injury and 1.6 million people go blind from ocular injuries worldwide. The vast majority of such injuries in the US (47.6%) occur between the ages of 18 and 45 years, while the remaining are about equally divided between the pediatric age group namely, below 18 years of age (25.4%), and adults 46 and older (26.9%).1
A century ago, the majority (>70%) of all serious ocular injuries occurred in the workplace due to lack of protective devices.2 More recently, however, sports and leisure activities have become a significant cause of ocular injuries, while nearly half (44.1%) of ocular injuries occur in the home.1 They arise from such common occurrences as accidental falls due to loose rugs and railings, hammering and/or drilling nails or screws, using hot curling irons or splattering of hot oil while cooking; household cleaners can also do their share of damage. Immediately outside of our houses, repairs and gardening offer more risks of injury — from clipping bushes and mowing the lawn to the use of power tools and bungee cords.
As to the area of eye involvement, the cornea is the most common (50.3%) site of injury, of which about half (43.8%) are superficial; that is, corneal abrasion. A close second is the conjunctiva, which accounts for 48.9% of injuries. The others, in descending order of occurrence, are as follows: eyelids (38.3%), anterior chamber (30.1%), retina (18.3%), orbit (15.4%), iris (14.1%), vitreous (13.5%), lens (11.4%), sclera (8.3%) and optic nerve (7.9%). Injuries, of course, often involve multiple sites.1
First Things First: Assessing the Injury
When the patient lands in your chair in an emergency situation, there are certain steps you must take immediately to assess the damage and provide appropriate treatment. Here are my guidelines for responding in those first crucial moments. Speed bumps or impact-absorbing structures like the orbit and eyelids, while dampening the blow to the globe, may not be able to fully protect the eye. When assessing the initial, post-traumatic ocular damage, it is important to prevent examination-induced iatrogenic ocular damage. If an examiner exerts undue pressure on an open globe, it may result in the loss of intraocular contents and thus add to the existing ocular damage — so avoid pressure on the globe! A lid block may be necessary in some cases and/or a lateral canthotomy. Additionally, protecting an open globe with a shield, and avoiding patching, is equally important until surgical intervention can be carried out.
First, quickly confirm whether there is a ruptured globe; history taking may be done subsequently. The emergency room physician will usually check for additional bodily injuries and, if necessary, get other specialties involved as a team approach. Avoid patching. Instead, place a shield over the injured eye. Radiological evaluation should include head and orbits; namely, plain film X-rays, CT scan of the orbits with fine cuts of 1 to 2 mm, along with coronal views to look for intraocular metallic foreign bodies. If you suspect an intraocular foreign body, do not order an MRI scan.
If the patient is unable to sit up for a slit-lamp exam, bedside evaluation with a penlight and indirect ophthalmoscope can provide useful information. Acuity should be recorded in the chart. Look for any eyelid and surrounding soft tissue injury. Palpate the orbital rim for any discontinuity and check for any orbital crepitus (subcutaneous emphysema). Check for any facial fractures. However, the initial focus should be to determine whether or not the globe is intact.
Tell-tale signs of a ruptured globe include a peaked pupil with shallow anterior chamber and hyphema. A corneal laceration with iris incarceration and iris prolapse is obviously an open globe. Other possible signs include iridodialysis, perforating lid injury, pronounced subconjunctival hemorrhage, vitreous hemorrhage and crystalline lens dislocation or IOL dislocation.
|Be Proactive About Prevention|
|Ninety percent of all ocular injuries can be prevented by using protective eyewear, so it is worthwhile to have a talk with your patients about this. Ask them if they engage in any activities that expose their eyes to injury; if so, they should use appropriate safety glasses. Here are some guidelines for helping patients find effective protection.|
The best choice of material for eye protection are polycarbonate or Trivex lenses (Table 1, page 30). Both lenses are thinner and lighter than plastic lenses, offer UV light protection and are up to 10 times more impact-resistant than plastic or glass lenses. For full protection, in addition to impact-resistant lenses, one should also choose optimal quality safety frames. Regular eyeglasses and frames do not provide adequate protection against trauma, and are not rated for use as safety glasses. This becomes even more important in one-eyed individuals.
|Table 1. Comparison of Polycarbonate and Trivex Lenses|
||Developed in 1970s for aerospace applications. Introduced for eye glasses in 1980s.
||Introduced in 2001|
||10% thinner than Trivex lenses (index of refraction = 1.58).
||10% thicker than polycarbonate lenses (index of refraction = 1.53).|
||10% heavier than Trivex lenses (higher specific gravity).
||10% lighter than polycarbonate lenses (lower specific gravity).|
||Injection molding — small solid pellets of polycarbonate are heated till they melt, injected into lens molds, compressed under high pressure, and cooled to produce a finished lens product within minutes.
||Cast molding — Similar to plastic lens manufacture. Has crisper optics than injection-molded polycarbonate lenses.|
||Comparable to Trivex.
||Comparable to polycarbonate lenses.|
|UV protection from sun's UV rays
||100% No need for UV-blocking lens coatings.
||100% No need for UV-blocking lens coatings.|
||Slightly less than Trivex.
||Less internal stress, hence, may produce sharper central and peripheral vision than polycarbonate lenses. Also, less chromatic aberration than polycarbonate lenses.|
||Available in greater variety of lens designs than Trivex, e.g., progressive lenses.
||Less variety than polycarbonate lenses.|
||Variable. May be more expensive than polycarbonate lenses.|
It is useful to look for a red reflex, the absence of which may be due to a retinal detachment or vitreous hemorrhage. Seidel test using a fluorescein strip or fluorescein stain can determine leaking aqueous humor from the anterior segment. Seidel test is positive when fluorescein turns bright green under the blue light of the cobalt blue filter in the slit-lamp.
Look for foreign bodies that may be obvious by slit-lamp examination or by radiological evaluation. If you find any, determine whether they are metallic or non-metallic, reactive or non-reactive.
As for that third channel of injury, chemical burns, obtain a history of acid or alkali injury. Immediate, copious eye irrigation with clean water at the location where the injury took place to dilute the chemical is of paramount importance. At the time of seeing the patient, irrigate the involved eye with normal saline or Lactated Ringer's solution, 2 liters, until that eye's pH is 7.0-7.5. Also, compare the pH to the opposite eye as a reference.
Following irrigation, assess the degree of tissue damage using the Hughes classification of ocular burns.
Grade 1: no ocular opacity and no limbal ischemia (prognosis = very good).
Grade 2: corneal haze with visible iris details and <1/3 limbal ischemia (prognosis = good).
Grade 3: corneal haze obscures iris details and limbal ischemia of 1/3 - 1/2 (prognosis = guarded).
Grade 4: opaque cornea with no view of pupil or iris and >1/2 limbal ischemia (poor prognosis).
For a non-ruptured globe with a chemical or thermal burn, perform a complete dilated eye examination, along with an IOP check.
When it comes to ascertaining fractures, enophthalmos (>2 mm) may be associated with medial wall or orbital floor fracture and usually require surgical repair. Muscle entrapment may be evaluated in a non-ruptured globe by positive forced duction test and CT scan.
Signs of blow-out fracture are:
1. Eyelids: edema and ecchymosis.
2. Muscles: ocular motility restriction, especially of vertical movements.
3. Sensation: entrapment of the infraorbital nerve can cause ipsilateral cheek hypesthesia or anesthesia.
4. Orbital and periorbital crepitus, i.e., subcutaneous emphysema.
In the Event of an Open Globe
If you determine that there is an open globe, carry out the following:
1. Order narcotics for pain (if no contraindication), IV antibiotics (check allergies) for prophylaxis and antiemetics as needed.
2. Tetanus immunization if needed.
3. Arrange for surgical repair: schedule the operating room, anesthesia. Inquire about the time of last meal.
4. Avoid ointment.
5. Do not applanate or check IOP by any method.
6. Avoid pupillary dilation.
7. Avoid motility evaluation.
8. If there is an orbital fracture, instruct the patient to avoid nose blowing.
• Choice of intravenous antibiotic prophylaxis for open globe: Intravenous vancomycin and ceftazidime (Fortaz) offers coverage against most common organisms associated with ocular injury. Vancomycin is a glycopeptide antibiotic. Ceftazidime is a third-generation cephalosporin; it is a semisynthetic, broad-spectrum, beta-lactam antibiotic for parenteral administration.
As for coverage, intravenous vancomycin provides good gram-positive coverage. It is effective against Staphylococcus, Streptococcus and Bacillus species.
Intravenous ceftazidime provides good gram-negative coverage, including Pseudomonas. It also has some gram-positive coverage as well.
Both vancomycin and ceftazidime given intravenously offer good intravitreal penetration.
• Dosage: Vancomycin HCL IV: Adults — 1 gram IV Q 12 hours (15 mg/kg IV administered Q 12 hours); Children — 10 mg/kg/dose IV in divided doses Q 6 hours, for a total of 40 mg/day in divided doses.
Ceftazdime: IV: Adults — usual dosage is 1 gram IV Q 12 hours (Q 8-12 h); Children — 100-150 mg/kg/day IV in divided doses Q 8 hours, maximum 6 grams/day.
Contraindications: Vancomycin is contraindicated in renal and auditory dysfunction. Both drugs are contraindicated if there is a history of allergy.
• Choice of intravitreal antibiotics: Similar to intravenous choice, intravitreal vancomycin and intravitreal ceftazidime are the drugs of choice. For use of intravitreal vancomycin, administer 1 mg/0.1 mL in 1.0 cc syringe. For intravitreal ceftazidime, dose 2.25 mg/0.1 mL in 1.0 cc syringe.
If there is penicillin allergy, use intravitreal gentamycin 100 micrograms/0.1 mL in 1.0 cc syringe or, alternatively, amikacin 200-400 micrograms/0.1 mL in 1.0 cc syringe. Amikacin may be preferred in this situation due to less potential toxicity as compared to gentamycin.
If treating Bacillus cerus, vancomycin is effective; alternatively, clindamycin 0.5 mg/0.1 ml may be used intravitreally. If the organism is fungal, use intravitreal amphotericin B 5 to 10 micrograms/0.1 mL.
Mechanism of Ocular Damage
• Blunt globe injury: Direct, blunt globe injury results in antero-posterior globe compression that causes equatorial globe stretching and may cause iridodialysis, angle recession, hyphema, lens zonular rupture with lens subluxation or dislocation, retinal dialysis, commotio retinae and choroidal rupture. The force of impact causes sudden flattening of the cornea with resultant increase in intraocular pressure. This results in anterior chamber compression, pupillary dilation that may lead to iris sphincter tears with traumatic mydriasis. Sudden peripheral displacement of the aqueous humor can cause angle recession, iridodialysis and hyphema.
Due to firm vitreous attachment to the peripheral retina, blunt trauma can cause peripheral retinal dialysis, which can lead to a retinal detachment. Vascular choroidal stretching can result in choroidal rupture with subretinal blood. In commotio retinae, both retinal edema and hemorrhage may be seen over a localized area. Vitreous hemorrhage may be present secondary to retinal blood vessel injury, uveal tract rupture, retinal tear or secondary to a scleral rupture. Blunt trauma causing a ruptured globe usually occurs beneath one of the rectus muscle insertion sites, around the optic nerve entrance posteriorly or at the corneo-scleral limbus.
• Penetrating injury: The extent of ocular damage depends on the regions traversed by the penetrating foreign body or sharp object. Localized corneal wounds may selfseal or there may be iris plugging the wound with pupillary distortion. If there is a through-and-through perforating globe injury, there may be lens, vitreous, retinal, choroidal and scleral damage, with or without optic nerve damage. Protective Bell's phenomenon with the eye rotating superiorly may cause inferior scleral injury.
• Intraocular foreign body (IOFB): Damage caused by IOFB may be twofold — first, by the direct passage within the eye, and secondly by tissue toxicity as the IOFB degrades or oxidizes. Sterile, glass and plastic IOFBs are well tolerated since they are nontoxic and inert. On the other hand, metallic foreign bodies are mostly magnetic, and those containing iron oxide can cause an inflammatory reaction such as siderosis if not removed in a timely fashion. Dreaded endophthalmitis can be secondary to vegetable matter within the eye.
• Burns: These may be due to radiant energy or chemical burns. Radiant energy burns may be secondary to contact with hot liquids, hot gases, hot metals or molten metals. Such thermal burns often cause cell death in the superficial epithelium, although thermal necrosis and penetration may occur. UV burns cause epithelial injury with punctate keratitis that can be very painful.
Chemical burns may be due to acid or alkali. Alkali cause more serious and permanent visual damage and blindness, depending on the extent and severity of the injury. Unlike acids, alkali are lipophilic and hence penetrate more rapidly into the eye. Alkali can cause liquefactive necrosis and saponification of the cell membrane fatty acids that result in cell disruption and death. Additionally, the hydroxyl ion hydrolyzes the intracellular glycosaminoglycans and denatures collagen.
This results in an inflammatory response with proteolytic enzymes being released that causes further tissue damage. Within about five to 15 minutes, alkali can enter the anterior chamber and damage the iris, trabecular meshwork, lens and the ciliary body. A pH value above 11.5 can cause permanent, irreversible ocular tissue damage.
With acid burns, there is protein coagulation on the corneal epithelium, which usually prevents further passage into the eye. Hence, these burns are superficial. The exception to this is hydrofluoric acid. Although a weak acid, it can quickly pass through cell membranes as it remains nonionized, thus causing liquefactive necrosis that is similar to alkali burn.
• Blow-out fracture: The orbital rim, being strong, absorbs and reflects any sudden trauma secondary to objects >50 mm in diameter, while at the same time it compresses the globe that translates into significant increase in the intraorbital pressure. This increased pressure can blow out the orbital walls. While the orbital floor (maxillary bone) is most susceptible, the medial wall (ethmoid bone) can also be affected.
Floor fracture can cause the globe to partially drop into the maxillary sinus, resulting in entrapment of inferior rectus or inferior oblique and enophthalmos. Muscle entrapment contributes to limited downgaze and inability toward upgaze. Medial wall fractures can cause damage to medial rectus muscle, but more importantly such fractures result in orbital emphysema due to direct communication between the orbit and the ethmoid sinus. The patient should be instructed to avoid blowing the nose. Additionally, there exists a risk of orbital cellulitis should pathogenic organisms from a sinus infection gain access to the orbit.
Treatment, Stage 2
Once you've made your initial assessment, you can turn your attention to long-term management of the injury. In the case of:
• Corneal abrasion. If foreign body is involved, evert the upper eyelids and remove any foreign bodies. Debride any loose corneal epithelium with jeweler's forceps. A bandage soft contact lens with topical antibiotics or antibiotic ointment and patch may be considered in non-contact lens wearers. A broad-spectrum antibiotic like besifloxacin (Besivance) eye drops may be used for prophylaxis against infection. Ketorolac (Acular) drops may be used during the initial two to three days, up to QID PRN for pain.
• Foreign bodies. Remove corneal and conjunctival foreign bodies. Administer topical antibiotics for prophylaxis against infection. Watch for any infectious infiltrates.
• Endophthalmitis. Aqueous/vitreous tap and culture. Administer intravitreal antibiotics (see above). After 12 to 24 hours of initial intravitreal antibiotics, early pars plana vitrectomy may be considered with repeated intravitreal antibiotics, especially if there is no clinical improvement. Early vitrectomy decreases the inflammatory debris, provides a large specimen for culture and sensitivity, and increases the possibility of a better final, visual outcome.
• Black eye (ecchymosis). Analgesics (avoid aspirin) and cool (ice) compresses may be used. Rule out ocular injury.
• Lid lacerations. Check for any canalicular and eyelid margin lacerations. Appropriate surgical repair should be performed. Check for ocular injury.
• Retrobulbar hemorrhage. A lateral canthotomy may be required in the presence of a retrobulbar hemorrhage that may be compromising central retinal artery perfusion with decreased visual acuity and an increased IOP.
• Traumatic optic neuropathy. If there is no contraindication, IV corticosteroids may be used, although their effectiveness is not fully proven. If CT scan without contrast shows evidence of optic sheath hematoma or a bone fragment pressing on the optic nerve, emergency surgical treatment may be indicated.
• Chemical burns. Irrigate the involved eye (see above). Prescribe topical steroid drops such as prednisolone acetate 1% every hour while awake for seven to 10 days, depending on the severity and response to treatment. Avoid using steroids for longer than 10 days as they may contribute to corneal melting. Provide antibiotic prophylaxis such as besifloxacin 0.6% TID, gatifloxacin 0.5% QID or moxifloxacin 0.5% QID. Perform cycloplegia using homatropine 5% or atropine 1% BID or TID.
Intraocular pressure control is important with topical and/or systemic medications. Administer sodium ascorbate to promote healing, 10% ophthalmic solution, one drop every two hours while awake and systemic sodium ascorbate 1 to 2 grams oral once daily. If melting, consider a collagenase inhibitor — tetracycline topical and/or systemic doxycycline 100 mg PO BID. Other agents to consider include 10% acetylcysteine drops every four hours (not fully proven to be clinically effective). Prescribe analgesics for pain. Bandage soft contact lens and lubrication as needed.
• Thermal burns: Ocular burns from ultraviolet radiation can be treated with antibiotic ophthalmic ointment and patching, which usually heals relatively fast within 24 to 72 hours with usually good, complete, visual recovery. Sometimes topical steroid drops may be indicated to decrease inflammation. Since there is significant pain associated with such injuries, analgesics should be used.
• Le Fort facial fractures: These involve the maxillary bone, usually bilaterally, and are either horizontal, pyramidal or transverse in involvement. Diagnosis follows physical exam with axial CT confirmation. To qualify for Le Forte fractures, the pterygoid plates should be involved:
(1) Le Fort I travels horizontally above the teeth apices and does not involve the orbits.
(2) Le Fort II fracture is pyramidal in shape, and involves the nasolacrimal system and the orbit. It extends from the nasal bridge and involves lacrimal bones, inferior orbital floor and rim, and passes thorough or near inferior orbital foramen. Additional facial bones are involved.
(3) Le Fort III involves the nasolacrimal system and the orbit, and can cause CSF rhinorrhea. It has a transverse shape and it involves the medial orbital wall via the nasolacrimal groove and ethmoid bones. It also involves the orbital floor along the inferior orbital fissure and extends to the lateral orbital wall as well.
With orbital fractures, check for facial sensation; namely, cranial nerve V1 (orbital roof) and V2 (orbital floor). Also rule out any traumatic optic neuropathy.
• Blow-out fracture. Orbital floor fractures with orbital content herniation may require surgery, especially with significant diplopia in primary gaze or down gaze, or if there is prominent enophthalmos. Surgery is helpful in cases of recent trauma. Surgical attempt at improving ocular motility after four weeks post trauma is usually met with failure. Waiting 10-14 days post trauma allows for edema and hemorrhage to diminish. The surgical procedure includes periosteal resection and fracture repair using bone graft or synthetic materials like silicon or Teflon. In uncomplicated ethmoid fractures, surgical repair of medial wall fracture is not indicated. Systemic antibiotic prophylaxis is used.
Whatever kind of injury you encounter, however, consider counseling for the patient to help him or her cope with severe traumatic eye injury and/or loss of an eye.
Watch Out for This By-product
Sympathetic ophthalmia is a granulomatous uveitis of both eyes after traumatic injury to one eye that can result in bilateral blindness. Ocular symptoms may develop over a range of days to several years after a penetrating injury. Earliest symptoms include loss of accommodation and floating spots. Although usually painless, this is not always the case — the patient may experience pain and photophobia.
The inflammatory disease process spreads through the uvea. Classic Dalen-Fuchs nodules may be visible, which represent focal choroidal infiltration. The retina is not directly involved, but retinal perivascular cuffing may be present. Other findings may include glaucoma, papilledema, poliosis and vitiligo. Management considerations with regard to prevention of sympathetic ophthalmia include enucleation versus evisceration of the injured eye within seven to 10 days after injury. The main treatment modality is immunosuppression.
Given that the majority of ophthalmic trauma occurs in the home, and the unlikelihood that most people wear protective eyewear for the common household tasks that may lead to injuries, it is imperative that eyecare specialists are up to date in their knowledge of emergency treatments.
Remember, these injuries are not just the province of hospital emergency rooms — they could walk into our practices at any moment. Our skill-set and promptness in treating traumatic injuries could mean the difference between sight and blindness for our patients. OM
1. Eye Injury Snapshot Data Summary, 2004 - 2008, American Academy of Ophthalmology and American Society of Ocular Trauma National Survey. http://www.aao.org/newsroom/guide/upload/Eye-Injuries-BkgrnderLongVersFinal-l.pdf. Accessed April 17, 2012.
2. Garrow A. A statistical enquiry into 1000 cases of eye injuries. BJO. 1923: 7(1):65-80.
||Thomas John, MD, a world leader in lamellar corneal surgery, is a clinical associate professor at Loyola University at Chicago, and in private practice in Oak Brook, Tinley Park and Oak Lawn, Ill. E-mail him at firstname.lastname@example.org.|
Ophthamology Management, Volume: 16 , Issue: May 2012, page(s): 22 - 32