Download Functional Vision Loss in Traumatic Brain Injuries Andy Chen, O.D

Functional Vision Loss in Traumatic Brain Injuries
Andy Chen, O.D, Sally Dang, O.D, Edward Chu, O.D, Paula Matsuno, O.D.
Long Beach Veteran Affairs Medical Center
5901 East 7th Street
Long Beach, CA 90822
Abstract
Functional vision loss from visual field constriction is a potentially significant consequence of TBI that can
be overlooked in “healthy” eyes. Patients with constricted visual fields may be legally blind and require
low vision services.
I. Case History
 Patient demographics: 44 year old White Male
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Chief complaint: Double vision while reading. He states his previous glasses had prism and
reports severe photophobia. He also reports it is hard to see and he bumps into things while
walking.
Ocular, medical history:
o POHx:
 History of traumatic brain injury
 Photophobia and glare sensitivity indoors and outdoors
 Convergence insufficiency
 Generally restricted vergence ranges at distance and near
 Myopia, Astigmatism, and Presbyopia
 Report of Visual Field Restriction
 (+) Ocular Trauma: metal lacerated temporal periocular region of left eye with
slight pain
o PMHx:
 Late effect of intracranial injury without mention of skull fracture
 1991: During the gulf war, a missile fired nearby and he sustained a
periocular injury with a piece of metal lacerating the left side of his face.
No loss of consciousness
 1999: During a training exercise in California, he went on top of the roof
to set up a machine gun. The building swayed and he fell through the
roof and the machine gun hit him in the back of his head. Loss of
consciousness for 30-40 minutes
 2004: Multiple vehicle accidents where the seat belts failed and he hit
the back of his head. No loss of consciousness
 2006: Reports falling out of a tree resulting in a concussion
 2009: Re-deployed OIF (Iraq) mission where riders isolated him and he
was kicked in the head. Brief loss of consciousness
 Traumatic brain injury with loss of consciousness
 Chronic Post-Traumatic Headache
 Visuospatial Deficit
 Chronic post-traumatic stress disorder
 Bothered by loud noises
 Migraines
 Vertigo
 While riding in a moving vehicle
 While walking down a hall or aisle in store
 While concentrating at near
 While walking in a crowd
 While approaching busy intersections
 Degeneration of lumbar intervertebral disc
 Cervical disc disorder
 Other signs and symptoms involving cognition
o FOHx and FMHx: Unremarkable
Medications:
 Acetaminophen 500 mg, Oxycodone 5mg/Acetaminophen 325mg, Rizatriptan 10
mg, Ondansetron 4 mg
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Other salient information: observed patient bumping into the right side of the doorway while
walking around in clinic
II. Pertinent findings
 Entrance Testing
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o Entering DVA (cc): OD 20/20, OS 20/20, OU 20/20
o Habitual SRx: OD -1.00 -0.50 x070, OS -1.50 DS
o EOMS, PUPILS: normal OU
o Cover test: orthophoria (cc) at distance, 10-12 PD Alt XT - 50% of the time (sc) at near
o Confrontation Visual Fields: Overall constriction to 20 degrees OD, OS
o Near point of convergence (break/recovery): 32cm/34cm (reduced, sc)
o Red Cap Desaturation: Normal OD, OS
o Color Vision: Normal OD, OS
Binocular Vision
o BCVA with MRx:
 Distance:
 OD: -1.25 -0.50 x070
20/20
 OS: - 1.75 DS
20/20
 Near:
 OD: +0.50 -0.50 x070 1BI
20/20
 OS: Plano DS
1BI
20/20
o NRA/PRA w/+1.50 over distance manifest
 NRA: +1.25
 PRA: +1.50
o Trialed framed adds, prefers +1.75
o Trialed framed prisms, 1-6 BI total, prefers 2.0 BI total at near only
o Trialed framed tints, prefers brown 2 at distance and blue 2 at near
o Von Graefe Phoria Testing:
 Near: 6 exophoria and orthophoria vertically
o AC/A: 1/1
o Smooth Vergences
 Near Base Out: x/8/-2 (reduced)
o Accommodation Testing - push up method
 OD,OS: 6.25D (exceeds expected age norms)
Ocular Health
o Anterior Segment: Normal OU
o Intraocular pressure: 14 mmHg OU
o Posterior Segment
 Vitreous, posterior pole, vessels, periphery: Normal OU
 ONH:
 C/D 0.50 rd; pink, distinct margins, (-) pallor, (-) edema OD
 C/D 0.50 rd; pink, distinct margins, (-) pallor, (-) edema, superior RNFL
myelination OS
 Macula: flat OD, OS
Ancillary Test
o Octopus Visual Fields
 GTOP (screener)
 OD: overall constriction to 20 degrees centrally
 OS: complete restriction to 5 degrees centrally
 M-Dynamic (10-2)
 OU: good reliability
 OD: overall constriction to 10 degrees
 OS: overall constriction to 7 degrees
Tangent Screens
 OD/OS: overall constriction consistent with automated visual fields
Physical: Uses a cane to ambulate
Laboratory studies/Radiology studies:
o Brain CT scans: Normal
o Brain MRI scans: Normal with no acute intracranial process
Others: VEP/ERG: patient schedule for follow up evaluation
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III. Differential diagnosis
 Primary/leading: Functional Vision Loss
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Others:
o Malingering
o Chronic papilledema
o Bilateral occipital lobe infarction with macular sparing
IV. Diagnosis and discussion
 Functional vision loss
Non-organic condition with an underlying psychological basis
Normal fundus appearance with no obstruction and overall healthy eye.
Part of an overall diagnosis from the Diagnostic and Statistical Manual called Conversion
Disorder
o Visual field constriction and decrease vision together are more common
o Functional vision loss in the form of constricted visual fields without reduced acuity is one
of the relatively less common symptom diagnosed in traumatic brain injury patients.
Because the ocular health exam is within normal limits, doctors may not order
appropriate visual field testing. Doctors need to be cognizant of the potential for
constricted visual fields in the TBI patient population.
Unique features
o Patient presented with common symptoms of TBI such as difficulty with near work and
severe photophobia. However, confrontation visual fields revealed severe constriction of
peripheral vision that was confirmed on formal visual field testing and tangent screen
Patient was found to be legally blind and was referred for low vision rehabilitation
services.
o When examining patients with history of TBI, clinicians should be wary of potential
functional field loss
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V. Treatment, management
 Treatment and response to treatment
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Prescribe Bi-optic Reverse Telescopes to expand patient’s field of view
 Trialed 1.7X and patient noticed a slight increase in field of view
 Trialed 2.2X and patient noticed a remarkable difference in his vision. So much
so, his mood was uplifted with a smirk and smile
Refer for orientation and mobility training
Blind Rehabilitation organization services evaluate patient’s activities of daily living in his
home environment
Consider a hand-held video magnifier to improved contrast and magnification for sustain
reading
Consider a CCTV with a maneuverable camera (Acrobat) to help with patient’s hobbies
such as bead making.
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Research
o A method to rule out malingering vs. functional vision loss is to perform
electroretinograms (ERG) and visual evoked potentials (VEP). A normal ERG with an
abnormal VEP suggests functional vision loss.
o Some other contributory factors for functional vision loss include star or jagged patterns,
clover leaf patterns, spiral patterns, and tubular/tunnel vision visual field defects.
o Although not proven, some evidence claim there is a cortical disconnect in the limbic
system within the cerebrum during functional vision loss.
Bibliography
o Beatty, S. “Non-Organic Visual Loss.” Postgraduate Medical Journal 75.882 (1999): 201–
207. Print.
o Bruce, Beau B, and Nancy J Newman. “Functional Visual Loss.” Neurologic clinics 28.3
(2010): 789–802. PMC. Web. 28 Aug. 2015.
o Pula J. Functional vision loss. Current Opinion in Ophthalmol. 2012 Nov;23(6):460-5.
o Rover J, Bach M. Pattern electroretinogram plus visual evoked potential: a decisive test in
patients suspected of malingering. Doc Ophthalmol 1987;66(3):245-51. Web. 28 Aug.
2015.
VI. Conclusion
 Clinical pearls, take away points if indicated
o Functional vision loss and visual field constriction may be overlooked and/or dismissed as
malingering in TBI patients particularly when the ocular health is normal. Clinicians need
to be aware of the potential for vision loss in cases of TBI and make sure their patients
are referred appropriately for low vision rehabilitation services as needed.
o Equally important is to recognize if the functional vision loss is affecting the patient’s
activities of daily living such as objects appearing out of nowhere while driving, walking,
grooming, cooking, etc.