Traumatic Ocular Disorders


Chapter 79

Traumatic Ocular Disorders



Ryan C. Young, James T. Banta



Definition


Ocular trauma encompasses a number of physical injuries, both mechanical and chemical, sustained by the eye (globe) and ocular adnexa. These tissues can sustain myriad different injuries, some of which are listed in Box 79-1. For nonophthalmologists, these injuries may seem complex and foreign. To facilitate classification and communication among health care professionals, a terminology system was devised to allow a standardized description and classification of ocular trauma.1,2 Table 79-1 lists the standard definitions that are used to describe traumatic ocular injuries.3




TABLE 79-1


Birmingham Eye Trauma Terminology
















































Term Definition Explanation
Eye wall Sclera and cornea Although the eye wall technically has three coats posterior to the limbus, for clinical and practical purposes, violation of only the most external structure is taken into consideration.
Closed globe injury No full-thickness wound of the eye wall
Open globe injury Full-thickness wound of the eye wall
Contusion No (full-thickness) wound of the eye wall The injury results from direct energy delivery by the object or from the changes in the shape of the globe.
Lamellar laceration Partial-thickness wound of the eye wall The wound of the eye wall is not “through” but “into.”
Rupture Full-thickness wound of the eye wall caused by a blunt object Because the eye is filled with incompressible liquid, the impact results in momentary increase of the intraocular pressure. The eye wall 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 caused by an inside-out mechanism.
Laceration Full-thickness wound of the eye wall caused by a sharp object The wound occurs at the impact site by an outside-in mechanism.
Penetrating injury Entrance wound If more than one wound is present, each must have been caused by a different agent.
Intraocular foreign body Retained foreign object(s) This is technically a penetrating injury but grouped separately because of different clinical implications.
Perforating injury Entrance and exit wounds Both wounds are caused by the same agent.

Modified from Kuhn F, Morris R, Witherspoon CD: Birmingham Eye Trauma Terminology (BETT): terminology and classification of mechanical eye injuries, Ophthalmol Clin North Am 15:139-143, 2002.


The most vital distinction is between open and closed globe injuries. This information is crucial because it determines the clinical management of the patient and provides important prognostic information.4 If the patient has not sustained a full-thickness injury, then the patient has a closed globe trauma. If there is a full-thickness wound, it is an open globe trauma. Closed globe trauma is further divided into contusions and lamellar lacerations. Contusions are the most common form of ocular injury and occur when the eye is impacted but the wall of the eye remains intact. The sequelae of an ocular contusion are vast and include corneal abrasion, hyphema, and iridodialysis. A lamellar laceration refers to a partial-thickness wound of the eye wall, but the integrity of the globe is maintained.


Full-thickness injuries are often inappropriately described and lead to confusion between a referring provider and the ophthalmologist. Too often, both primary care providers and ophthalmologists describe a patient who has sustained a full-thickness injury to the globe as having a “ruptured globe.” This is correct only if the person has sustained an ocular contusion (typically with a blunt object) resulting in a rupture of the eye wall. Common mechanisms for a ruptured globe include high-velocity projectiles (e.g., racquetball, bungee cord) and assault (e.g., fist, bat, paintball). These injuries are highly destructive to intraocular contents and have a guarded prognosis in all instances. By contrast, if a sharp object creates a full-thickness eye wall injury, it is classified as a laceration. Common mechanisms of lacerations include work-related activities (e.g., cutting tile, landscaping) and accidents (e.g., children playing with scissors). Lacerations can be further divided into penetrating injuries, perforating injuries, and intraocular foreign bodies. Penetrating injuries penetrate through the eye wall without an exit wound, whereas perforating injuries have both an entry and an exit wound. An intraocular foreign body is present when a portion of the insulting object enters and remains in the eye.



Epidemiology


The annual number of eye injuries treated by medical personnel was estimated at nearly 2 million by a large national survey.5 The Baltimore Eye Survey reported a cumulative lifetime prevalence of eye injury of 14.4% in the general population of an urban area.6 McGwin and colleagues estimated the rate of injury to be 6.98 injuries per 1000 persons. Of those injuries, 50.7% were treated in emergency departments, 38.7% in private offices of physicians, 8.1% in outpatient facilities, and 2.5% within inpatient facilities. Not surprisingly, most injuries were sustained by men younger than 30 years.5,7 The most commonly encountered injuries were superficial injuries of the eye and adnexa and foreign bodies on the ocular surface.5


An interesting aspect of ocular trauma is its recurrent nature. In the Beaver Dam Eye Study, Wong and coworkers noted that an initial episode of ocular trauma increased the likelihood of recurrent trauma in the next 5 years by a factor of 3.27.8 The rates of injury were also higher among blue collar and farm workers compared with white collar workers, with odds ratios of 1.58 and 1.32, respectively. Epidemiologic studies such as these assist in identifying at-risk populations and creating appropriate prevention strategies. For example, Dannenberg and associates found in their study of penetrating ocular trauma in the workplace that only 6% of the injured were wearing protective eyewear at the time of their injury,9 clearly highlighting the need for protective eyewear in high-risk settings.


Children are not immune to ocular trauma. Open globe injuries are among the most serious of ocular injuries, and one study has shown that up to 43% of these injuries are sustained in patients younger than 18 years.10 A large study of pediatric globe injuries in Los Angeles demonstrated that sharp objects cause the majority of injuries (67%) and that most injuries occur at home (72%).11

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Oct 12, 2016 | Posted by in CRITICAL CARE | Comments Off on Traumatic Ocular Disorders

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