Visual Function in Patients of a Polytrauma Rehabilitation Center: A Descriptive Study

Abstract

Little is known about the visual function deficits associated with polytrauma injury. In this retrospective descriptive study, we examined the records of a clinic established to assess visual function in patients experiencing deployment-related polytrauma. We describe the clinical findings and present a vision examination protocol that may be useful for screening polytrauma patients in other settings. Data from our sample suggested that self-reported vision complaints were common (74%) and confirmed that visual impairment occurred in 38% of all cases. When examining the mechanism of injury, we found that polytrauma due to blast injuries appeared to more than double the risk of visual impairment compared with all other polytrauma causes (i.e., motor vehicle accidents, gunshot and/or shrapnel, assault, falls, or anoxia). The rate of visual impairment in blast-related injury was 52% compared with 20% for all other sources of injury. Visual complaints and impairments were common in the polytrauma patients studied. This finding suggests that comprehensive eye examinations should be routinely administered, particularly when the mechanism of injury involves a blast.

Introduction

Blindness and visual impairment have long been recognized as consequences of war. The eyes encompass only about 0.25 percent of the surface area of the body. Current estimates, however, suggest that injuries to the eyes are 20 to 50 times greater than would be predicted by their relatively small surface area [1–2]. Ocular injuries in World War I constituted between 2.5 and 3.0 percent of all injuries, while in Operations Desert Shield and Storm (1991), they accounted for 13 percent of all injuries [1]. The use of explosive devices has led to an increased number of military personnel with traumatic brain injury (TBI) as a result of combat or related events. TBI may damage the visual pathway, visual cortex, and/or pathways that connect the eyes to cortical visual centers. Other sensory and motor areas, as well as areas governing memory, cognition, motor control, and emotion [3], may also be damaged. Thus, injuries to either the eye or brain may result in vision loss or blindness in addition to other functional, emotional, and mental impairments.

Between January 2003 and March 2006, 28 percent of the patients evacuated to Walter Reed Army Medical Center received a diagnosis of TBI and the Defense and Veterans Brain Injury Center classified more than half of these cases as moderate or severe [4]. In a study at the Department of Veterans Affairs (VA) Palo Alto Health Care System (VAPAHCS), 74 percent of 38 combat-related TBI patients in the Polytrauma Rehabilitation Center (PRC) had blast exposure [3]. The relatively high rate of eye injuries may be related to the increased number of head injuries associated with blasts caused by bombs, grenades, rockets, or other explosives as compared with other mechanisms of injury such as gunshots [5–6]. The increased incidence of head and eye injuries has led to continuing efforts to develop better head armor for soldiers [7].

While injuries to the eye and brain have been highlighted in the polytrauma and related literature, little or no attention has been given to the nature of the vision loss. The Veterans Health Administration clinical directive has defined “polytrauma” as injury to the brain concurrently with injury to several other body areas or organ systems that results in physical, cognitive, and psychosocial impairments.* The lack of understanding of vision loss and its possible interaction with brain injury may interfere with effective rehabilitation. A similar situation exists in the stroke and TBI literature. Zihl [8] and Biehl et al. [2] have noted that central visual and oculomotor disorders occur in 20 to 40 percent of neurological rehabilitation center patients, and Gianutsos reported that about half of head trauma patients exhibit visual system disorders that have not been assessed despite previous hospital treatment [9]. Kerkhoff suggested that two factors explain the lack of eye examinations and treatment: limited financial resources in healthcare and the belief that central visual disorders do not require treatment, since they do not adversely affect outcome [10]. Kerkhoff questioned the validity of that belief and presented evidence that although selected training activities do not restore normal function, they do increase independence and perceived quality of life [10].

Visual impairments adversely affect the subjective quality of life of institutionalized [10] and noninstitutionalized [11–12] individuals. On a functional level, visual impairments reduce the individual’s ability to perform such common tasks as reading, activities of daily living, facial recognition, and travel. Visual impairments are also associated with increased length of hospitalization [13], risk of falls and hip fracture [14–15], and mortality [16– 17]. Experience in the VA Blind Rehabilitation Service has shown that prescribing optical devices and specialized rehabilitation interventions restores independent function in cases of severe visual impairment, including blindness.

The brain is particularly susceptible to high-impact injuries and, as Lew noted [18], compensation strategies for rehabilitation rely heavily on the brain. Vision can play an important role in polytrauma rehabilitation since walking, reading, face recognition, orientation, shopping, meal preparation, grooming, and a myriad of other daily activities derive most of their sensory input from the visual system. An estimated 70 percent of all human sensory processing is affected by information from the two eyes [19]. Unrecognized or uncorrected refractive errors, photosensitivity, or more severe visual and/or perceptual impairment in polytrauma patients are likely to negatively affect rehabilitation efforts. Uncorrected refractive errors, for example, may reduce performance on penand- paper neuropsychological tests. Progress in the rehabilitation of activities of daily living may be impeded if the patient cannot clearly see labels, read directions, or recognize common objects. More severe visual impairments, such as hemianopsia or visual neglect, may hinder physical therapy for walking or wheelchair use and increase balance problems and fall risks.

The severe combination of disabilities presented by polytrauma patients is an unprecedented challenge for rehabilitation facilities. This challenge has led some to propose that, while acute emergency-based medical care is well described, it may not be an adequate model for treating this unique population in rehabilitation settings, particularly when patients have blast-related injuries. Scott and colleagues proposed mechanism of injury as the preferred model for comprehensively assessing and treating blast-related polytrauma cases [20]. A major advantage of this model appears to be its focus on the typical sequelae given the mechanism of injury, which increases the likelihood that related conditions will be detected. Undetected visual impairment, for example, can be masked by symptoms associated with problems in cognition and communication, posttraumatic stress disorder, or other conditions common in polytrauma patients.

The current study quantified and analyzed the results of comprehensive vision examinations conducted on a cohort of polytrauma patients who were deployed in conjunction with Operation Iraqi Freedom (OIF) or Operation Enduring Freedom (OEF). These patients’ injuries occurred either during combat or deployment-related activities. For example, all injuries from a blast event were combat-related, as were gunshot and/or shrapnel wounds. Motor vehicle accidents (MVAs) were not always combat-related. All injuries due to falls were non-combat-related.

For this article, we defined “vision deficits” broadly to encompass conditions such as uncorrected refractive error and photosensitivity as well as more significant vision losses such as visual impairment and blindness. We also report on patients who had visual perceptual deficits (e.g., visual neglect or inattention) and/or difficulty reading (e.g., inability to comprehend at a fifth-grade level, scan or track lines of text, or read fluently as rated by the examining optometrist) even though their visual acuity may have been normal or near normal. Of note, the vision examinations revealed conditions that likely existed before injury (e.g., refractive error) in addition to conditions that appeared to be sequelae of the events that resulted in the polytrauma injury. However, drawing cause-and-effect conclusions is beyond the scope of the current article. Rather, our focus is on elucidating those visual characteristics of a cohort of polytrauma patients that may limit or impede rehabilitation.

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