Ocular Trauma: Principles and Practice

Transcription

1 Ocular Trauma: Principles and Practice von Dante J. Pieramici Ferenc Kuhn 1. Auflage Thieme 2002 Verlag C.H. Beck im Internet: ISBN Zu Leseprobe schnell und portofrei erhältlich bei beck-shop.de DIE FACHBUCHHANDLUNG

2 SECTION I GENERAL CONSIDERATIONS

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4 Chapter 1 BETT: THE TERMINOLOGY OF OCULAR TRAUMA Ferenc Kuhn, Robert Morris, and C. Douglas Witherspoon CURRENT PROBLEMS Trauma can result in a wide spectrum of tissue lesions of the globe, optic nerve, and adnexa, ranging from the relatively superficial to vision threatening. Our understanding of the pathophysiology and management of these disorders has advanced tremendously over the last 30 years, and it is critical that a standardized classification system of terminology and assessment be used by both ophthalmologists and nonophthalmologists when describing and communicating clinical findings. A uniform classification system enables this accurate transmission of clinical data, facilitating the delivery of optimal patient care as well as further analysis of the efficacy of medical and surgical interventions. Without a standardized terminology of eye injury types, it is impossible to design projects such as the development of the OTS, to plan clinical trials in the field of ocular trauma, and to communicate unambiguously between ophthalmologists. Multiple examples from the literature demonstrate the lack of definitions, with obvious implications. Blunt injury If the consequences are blunt, it is a contusion (closed globe injury). 1 If the inflicting object is blunt, it is either a contusion or a rupture (open globe injury). 2 To add to the confusion, the two terms have even been thrown together as contusion rupture. 3 Because the word blunt is ambiguous and contusion and rupture have vastly different implications, it is best to eliminate blunt from the eye injury vocabulary. Blunt nonpenetrating globe injury 3 Do sharp nonpenetrating injuries also occur? Blunt penetrating trauma 4 Aren t all penetrating injuries sharp? Sharp laceration 5 Is there a laceration that is blunt? Blunt rupture 6 Is there a rupture that is sharp? An unambiguous system in ocular traumatology must satisfy the following three criteria. 1. Each term has a unique definition. Currently, it is exceptional that definitions in publications are provided at all or that their use is enforced No term can be applied for two different injuries. Unfortunately, numerous examples show that the same term is used to describe two distinctly different clinical entities. For example, perforating can mean an injury with an entrance wound only 8 or one with both an entrance and an exit wound No injury is described by different terms. Unfortunately, numerous examples show just the opposite. For example, an injury with both entrance and exit wounds is referred to as double penetrating, 10 double perforating, 11 and perforating, 12 or the same injury is alternatively referred to either as penetrating or as perforating even within the same article. 13 3

5 4 SECTION I GENERAL CONSIDERATIONS BIRMINGHAM EYE TRAUMA TERMINOLOGY a BETT satisfies all criteria for unambiguous standard terminology by: providing a clear definition for all injury types (Table 1 1); and placing each injury type within the framework of a comprehensive system (Fig. 1 1). The key to BETT s logic is to understand that all terms relate to the whole eyeball as the tissue of reference. b In BETT, a penetrating corneal injury is unambiguously an open globe injury with a corneal wound; the same term had two potential meanings before: 1. An injury penetrating into the cornea (i.e., a partialthickness corneal wound: a closed globe injury) or 2. An injury penetrating into the globe (i.e., a fullthickness corneal wound: an open globe injury). BETT 15 has been endorsed by several organizations including the American Academy of Ophthalmology, International Society of Ocular Trauma, Retina Society, United States Eye Injury Registry and its 25 international affiliates, Vitreous Society, and the World Eye Injury Registry. It is mandated by several journals such as Graefe s Archives, Journal of Eye Trauma, Klinische Monatsblätter, and Ophthalmology. Therefore, it is desirable that BETT becomes the language of everyday clinical practice. a Standardizing injury types also has far-reaching prognostic implications (see Chapter 3). For instance, many variables characterize an object (e.g., aerodynamics, kinetic energy). 14 The most important, kinetic energy (E), is determined by the mass (m) and the velocity (v); E = 1 2mv 2. Blunt objects need higher kinetic energy to enter the eye (rupture) and are thus capable of inflicting more damage than sharp objects (laceration). Even when the blunt object causes a closed globe injury (contusion), the visual consequences can be more devastating (e.g., choroidal rupture at the fovea) than in eyes with an open globe trauma (e.g., retinal tear). b When the tissue of reference changes, the terminology must reflect that; for example, in the sentence in Chapter 24: The IOFB must possess certain energy to perforate the eye s protective wall, the tissue of reference is obviously the sclera/cornea. If the object penetrates either of these tissues, it does not become intraocular but remains intrascleral/corneal (see reference 72). Perforation means that the object entered the tissue on one side and left it on the other side, thus becoming an IOFB. TABLE 1 1 Term TERMS AND DEFINITIONS IN BETT* Definition and Explanation Eyewall Closed globe injury Open globe injury Contusion Lamellar laceration Rupture Laceration Penetrating injury Perforating injury Sclera and cornea Although technically the eyewall has three coats posterior to the limbus, for clinical and practical purposes, violation of only the most external structure is taken into consideration No full-thickness wound of eyewall Full-thickness wound of the eyewall There is no (full-thickness) wound The injury is due to either direct energy delivery by the object (e.g., choroidal rupture) or the changes in the shape of the globe (e.g., angle recession) Partial-thickness wound of the eyewall Full-thickness wound of the eyewall, caused by a blunt object Because the eye is filled with incompressible liquid, the impact results in momentary increase in IOP. The eyewall yields at its weakest point (at the impact site or elsewhere; e.g., an old cataract wound dehisces even though the impact occurred elsewhere); the actual wound is produced by an inside-out mechanism Full-thickness wound of the eyewall, caused by a sharp object The wound occurs at the impact site by an outside-in mechanism Entrance wound If more than one wound is present, each must have been caused by a different agent Retained foreign object(s) Technically a penetrating injury, but grouped separately because of different clinical implications Entrance and exit wounds Both wounds caused by the same agent *Some injuries remain difficult to classify. For instance, an intravitreal BB pellet is technically an IOFB injury. However, because this is a blunt object that requires a huge impact force if it enters, not just contuses, the eye, there is an element of rupture involved. In such situations, the ophthalmologist should either describe the injury as mixed (i.e., rupture with an IOFB) or select the most serious type of the mechanisms involved (see Chapter 3).

6 CHAPTER 1 BETT: THE TERMINOLOGY OF OCULAR TRAUMA 5 Injury Closed globe Open globe Contusion Lamellar laceration Laceration Rupture Penetrating IOFB Perforating Figure 1 1 BETT. The double-framed boxes show the diagnoses that are used in clinical practice. REFERENCES 1. Joseph E, Zak R, Smith S, Best W, Gamelli R, Dries D. Predictors of blinding or serious eye injury in blunt trauma. J Eye Trauma. 1992;33: Russell S, Olsen K, Folk J. Predictors of scleral rupture and the role of vitrectomy in severe blunt ocular trauma. Am J Ophthalmol. 1988;105: Liggett PE, Gauderman WJ, Moreira CM, Barlow W, Green RL, Ryan SJ. Pars plana vitrectomy for acute retinal detachment in penetrating ocular injuries. Arch Ophthalmol. 1990;108: Meredith TA, Gordon PA. Pars plana vitrectomy for severe penetrating injury with posterior segment involvement. Am J Ophthalmol. 1987;103: De Juan E, Sternberg P Jr, Michels RG. Penetrating ocular injuries. Ophthalmology. 1983;90: Klystra JA, Lamkin JC, Runyan DK. Clinical predictors of scleral rupture after blunt ocular trauma. Am J Ophthalmol. 1993;115: Alfaro V, Liggett P. Vitreoretinal Surgery of the Injured Eye Philadelphia: Lippincott Raven; Punnonen E, Laatikainen L. Prognosis of perforating eye injuries with intraocular foreign bodies. Acta Ophthalmol. 1989;66: Ramsay RC, Knobloch WH. Ocular perforation following retrobulbar anesthesia for retinal detachment surgery. Am J Ophthalmol. 1978;86: Ramsay RC, Cantrill HL, Knobloch WH. Vitrectomy for double penetrating ocular injuries. Am J Ophthalmol. 1985;100: Topping TM, Abrams GW, Machemer R. Experimental double-perforating injury of the posterior segment in rabbit eyes. Arch Ophthalmol. 1979;97: Hutton WL, Fuller DG. Factors influencing final visual results in severely injured eyes. Am J Ophthalmol. 1984;97: Hassett P, Kelleher C. The epidemiology of occupational penetrating eye injuries in Ireland. Occup Med. 1994;44: Dziemian A, Mendelson J, Lindsey D. Comparison of the wounding characteristics of some commonly encountered bullets. J Trauma. 1961;1: Kuhn F, Morris R, Witherspoon CD, Heimann K, Jeffers J, Treister G. A standardized classification of ocular trauma terminology. Ophthalmology. 1996;103: