The Management of Corneal Trauma Advances in the Past Twenty-Five Years
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Cornea 19(5): 617–624, 2000. © 2000 Lippincott Williams & Wilkins, Inc., Philadelphia The Management of Corneal Trauma Advances in the Past Twenty-five Years Marian S. Macsai, M.D. Summary. Over the past quarter century, advances in our under- tective eye wear, helmets, and other gear during sporting events standing of corneal anatomy, physiology, and wound healing have has prevented some injuries in recent years. However, newer ac- all played an integral role in the management of corneal trauma. As tivities such as “paint ball” and the “potato gun” have produced the etiologies of corneal trauma have changed, so has our under- significant contusive ocular injuries.4 Corneal foreign bodies (FBs) standing of the impact of injury on corneal function as it relates to from animal origins (bee stings, caterpillar hairs) vegetable matter, visual rehabilitation. Numerous new classes of antibiotics, antiin- minerals, plastic, glass, stone, nails and fish hooks have all been flammatory agents, and tissue adhesives have emerged. Occlusive 5–12 therapy has advanced from simple pressure patching bandage soft described. Despite the recommendation of safety glasses, frag- contact lenses and collagen shields. Surgical instrumentation, op- ments of nylon cord from modern electric weed trimmers have 13 erating microscopes, viscoelastic substances, and suture materials resulted in penetrating ocular injury. Although occupational have all improved the outcomes of corneal trauma repair. Im- trauma is a common cause of penetrating ocular injuries,14–17 mo- proved understanding of the refractive properties of the cornea tor vehicle accidents and air bags have been reported to account for through topography and alternative suture techniques has helped up to 30% penetrating ocular trauma.18–20 us restore the natural corneal curvature and visual outcomes. Con- Compulsory seat belt legislation, the universal presence of lam- sequently, in the last quarter of this century our therapeutic ap- inated windshields, and air bags have been introduced as mecha- proaches to cornea trauma, both medical and surgical, have im- nisms to reduce the consequences and incidence of injuries result- proved. ing from motor vehicle accidents. Although the incidence of lethal Key Words: Cornea—Foreign bodies—Trauma—Corneal abra- sions—Corneal lacerations—Ocular trauma—Classification— injuries from motor vehicle accidents has been greatly reduced by Terminology—Perforations—Prognosis—Suture—Wound repair. the introduction of air bags, ocular injury may result from either the air bag itself or contusion from the driver’s eyeglasses.21 CLASSIFICATION PATIENT EVALUATION The introduction of specific ocular terminology has improved The initial evaluation of a patient with ocular trauma has not our ability to compare outcomes between different studies, to iden- changed significantly over the past 25 years. The initial examiner tify prognostic features, and to evaluate overall outcomes of eye 1 may be the first and only physician to obtain a clear view of the trauma. Kuhn et al. proposed specific ocular trauma terminology posterior pole and optic nerve; therefore, a logical, thorough ap- to promote uniform use. After initial endorsement of this termi- proach to the examination is needed.22 Determination of the source nology by the American Academy of Ophthalmology and the In- and composition of FBs has advanced significantly over the past ternational Society of Ocular Trauma, the ocular trauma classifi- 25 years. In the case of a metallic FB, a negative plain radiograph cation group established a categorical classification of mechanical 2 may eliminate the need for further, more expensive and invasive injuries to the eye. This classification system was designed for use tests. However, nonmetallic FBs such as wood, plastic, or glass are by ophthalmologists and non-ophthalmologists. In this classifica- not easily seen on plain x-ray films. Computed tomography is now tion, both anatomic and physiologic variables of prognostic value the standard diagnostic test for imaging the traumatized eye and in determining visual outcome have been identified. These vari- orbit. Current generation computed tomographic machines can de- ables include the type of injury, the grade of injury based on visual tect nonmetallic radiolucent FBs 1 mm in size. Axial sections of acuity at initial examination, the presence of a relative afferent the orbit should be no greater than 1.5 mm apart and, in the case pupillary defect in the involved eye, and the zone of injury based of a suspected small FB, overlapping slices may be requested.23,24 on location of the globe opening. Bone-free projections are used to detect small radiolucent FBs. The leading cause of blindness in young adults is trauma, fre- 3 Magnetic resonance imaging can detect a wide variety of veg- quently sustained during recreational activities. The use of pro- etable, plastic, glass, and radiolucent FBs in the eye.25–28 How- ever, magnetic resonance imaging is not useful in identifying mag- Submitted January 30, 2000. Revision received March 7, 2000. Ac- netic FBs and may not be readily available preoperatively. cepted March 8, 2000. From the Division of Ophthalmology, Evanston Northwestern Health- care, Northwestern University Medical School, Evanston, Illinois, U.S.A. CONTUSION INJURIES Address correspondence and reprint requests to Dr. Marian S. Macsai, Chief, Division of Ophthalmology, Evanston Northwestern Healthcare, In the event of blunt trauma, the examiner must remain alert of 2650 Ridge Avenue, Evanston, IL 60201, U.S.A. possible rupture of te globe. Scleral rupture occurs most com- 617 618 M.S. MACSAI monly behind the insertions of the rectus muscles. However, in the blunt instrument or a diamond burr to smooth the underlying Bow- patients who have undergone incisional keratotomy (radial or as- man’s layer may induce normal re-epithelialization. Anterior stro- tigmatic), the areas of previous incisions are the most likely point mal puncture has been successful in some patients.46,47 of rupture in blunt trauma.29–31 Stromal puncture is a method of mechanically implanting epi- Contusion injuries of the corneal endothelium, initially identi- thelial cells into Bowman’s layer; thereby inducing localized fi- fied by Pichler in 191632 as disciform lesions resulting from mili- broblast proliferation and adhesion of the corneal epithelium. This tary explosion injuries, may occur without stromal or Descemet’s simple technique can be performed with minimal instrumentation membrane tears. Cibis et al.33 described the etiology, pathophysi- at the slit-lamp; however, when performed in the cornea visual ology, and prognosis of traumatic corneal and endothelial rings. access stromal puncture may result in significant glare or de- The most likely explanation of the ring-shaped disruption of en- creased vision. Recently, phototherapeutic keratectomy has been dothelial cells is the shock wave generated through Bowman’s evaluated as a treatment for recurrent corneal erosions.48–53 When membrane, stroma, and Descemet’s membrane to the endothelium compared to debridement, phototherapeutic keratectomy with the resulting in swollen endothelial cells that appear to completely excimer laser has a lower incidence of recurrence; however, access resolve within a few days.33 to an excimer laser may be difficult for some surgeons and the cost may be prohibitive. CORNEAL EROSIONS FOREIGN BODY The management of traumatic corneal erosions has evolved dur- The technique of corneal FB removal has not changed signifi- ing the past 25 years, as has our understanding of corneal wound cantly over the past 25 years. However, the ability of non- healing.34 Antibiotic ointment, with or without a topical mydriatic ophthalmologists to remove corneal FBs at the slit-lamp, using the agent and pressure patch, has been the traditional mainstay treat- tip of a disposable needle, has increased patient access to health ment of traumatic corneal erosions. The result of this therapy is the care. Emergency room physicians and primary care physicians loss of binocular vision, and numerous authors have suggested that with access to a slit-lamp can easily learn to remove corneal FBs the presence of a corneal pressure patch may retard healing.35,36 primarily and can monitor patients for postoperative corneal re- Double patching in which the injured and uninjured eye are both epithelialization. Visually significant FB scars that are present in occluded has been shown to produce more rapid healing by de- the very anterior portion of the corneal stroma may be removed by creasing ocular movement; however, this treatment is not feasible phototherapeutic keratectomy.54,55 for the vast majority of patients.37 Collagen shields and the use of soft contact lenses were investigated for the use of traumatic cor- PREOPERATIVE MANAGEMENT neal abrasions and, initially, were found to be expensive alterna- tive therapies.38,39 Once a corneal perforation is detected, the ophthalmologist must Numerous studies have been done to compare pressure patching decide if treatment can be performed at the slit-lamp or if surgical to no patching for corneal abrasions (due to trauma or FB removal) intervention in the operating room is warranted. Management of and have concluded that the use of eye patching is not mandatory full thickness corneal injuries and areas of tissue loss >2 mm for healing to occur. Uninfected, non-contact lens-related trau- usually require surgical intervention in the operating room. In matic