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Developing a Consensus Vision Screen for Patients with Mild Traumatic Brain Injury
Gregory L Goodrich, PhD
VA Palo Alto Health Care System, Palo Alto, CA
Palo Alto, CA
Funding Period: July 2011 - September 2012
Over 180,000 troops serving in Afghanistan and Iraq have sustained a mild traumatic brain injury (mTBI). Prior research has shown that mTBI may cause disorders of the binocular and oculomotor visual systems. Such disorders present with clinical symptoms including blurred or double vision (diplopia), convergence and/or accommodative deficits, and pursuit and saccade deficiencies among others. Patients suffering these symptoms may experience difficulty in performing daily living activities that rely upon vision. A particularly severe problem is difficulty or inability to read. While these deficits are visual patients may not recognize the visual nature of the problem and attribute the visual difficulty to other factors including inability to concentrate, memory issues, lack of interest/motivation, or other symptoms commonly associated with mTBI. Diagnosis of binocular/oculomotor deficits requires examination techniques which are not routinely provided in optometry settings and no tool for effective screening currently exists aside from time-consuming, comprehensive examinations. Such comprehensive examinations would exceed the capacity of VA eye care personnel to provide.
Optometrists in the VA are responsible for over 1.5 million patient visits annually. A survey of some 600 VA optometrists serving active duty personnel and veterans with mTBI was conducted in 2011 and found that over 70% of respondents served mTBI patients. The settings in which these optometrists worked spanned the range of VA medical centers, clinics, and outpatient settings. However, there is no standard of care for binocular/oculomotor examinations. Thus, there is a need for an examination protocol, amenable to VA and other (e.g. Department of Defense) settings, which would allow eye care providers to efficiently screen mTBI patients so that referrals for appropriate care can be made. Such referrals would correct or ameliorate the visual problems experience by these patients and contribute to an improved quality of life.
The study developed a collaborative group of 16 VA optometrists who are experienced in providing binocular/occulomotor examinations to form an expert panel. The panel will define a) what patient history elements need to be included in an optometric screen for visual dysfunctions? and b) what examination elements should be used in the screen. The end product of the study will be a binocular/occulomotor dysfunction screen useable within VA optometry. It will also form the basis for further research to validate the screen and to ultimately assist in estimating the prevalence of binocular/occulomotor dysfunctions in veterans with mTBI.
A modified Delphi method was employed to elicit opinions from a team of expert participants regarding vision evaluation of the mTBI patient, including case history questions and exam procedures. Sixteen optometrists from nine states and a wide variety of optometry settings served as the expert panel. Two Delphi rounds were conducted for the patient history and two rounds were conducted for the examination portion. The original items for the Delphi rounds were selected from VHA Directive 2008-065, current literature sources, and history and examination items submitted by participating experts. The initial history survey had 40 questions and the examination survey contained 43 items. Routine eye examination procedures (e.g. visual acuity) were not included as these are routinely done in all eye care settings. Participants rated each item on a 5-point Likert scale (strongly disagree, disagree, neutral, agree, strongly agree). Participants were encouraged to make comments about any item and were provided feedback on the prior round results before the second round. Items were rejected if less than 50% of responses were marked "agree" or "strongly agree". Agreement (consensus) was defined as 80% (e.g. rated "agree" or "strongly agree") for item inclusion. Items not rejected or accepted in the first round were resubmitted during the second round. Items not accepted following the second round were rejected.
The Delphi methodology resulted in a patient history consisting of 17 items covering a range of issues including pre-post mTBI-causing event, neurological history, specifics of the TBI-inducing event and ocular injuries. The methodology resulted in seven items to measure oculomotor, accommodative, and binocular vision function. The resulting history and examination mTBI screen provides an expert-driven protocol which can be used to screen mTBI patients for binocular/oculomotor deficits in VA and other eye care settings.
Binocular vision and oculomotor dysfunctions affect a very high percentage of veterans incurring mild traumatic brain injury. These dysfunctions negatively impact educational, vocational, and social activities and may adversely affect treatment for other disorders associate with mTBI. At present there is no recognized clinical screen to detect these dysfunctions. Additionally, VA optometrists already serve a large number of VA patients and the resources available to address visual consequences of mTBI are severely constrained. The current project utilized a modified Delphi technique to provide an evidence based screen which potentially addresses a known need within VA healthcare.
Concurrently the Department of Defense and Department of Veterans Affairs Vision Center of Excellence created an initiative to develop clinical practice guidelines related to vision loss and dysfunction in troops incurring traumatic brain injury. The current study provided an evidence-based binocular/oculomotor screen that has been incorporated into the draft clinical practice guidelines. Thus the current project has shown an impact beyond the VA.
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DRA: Brain and Spinal Cord Injuries and Disorders
MeSH Terms: none