BASICS
DESCRIPTION
• Vision loss in the absence of contributory ocular or neurologic pathology
– Multiple labels
– Functional
– Hysterical
– Psychosomatic
– Conversion reaction
– Munchausen’s syndrome
– May be psychogenic or the result of malingering
Malingering symptoms are consciously and voluntarily produced
EPIDEMIOLOGY
Prevalence
• 1–5% of visual problems seen by ophthalmologist 1A, 2A
• Decreased visual acuity most common
– Most prevalent in children and young adults
– Psychogenic more common in children and young adults
– Females > Males
– Malingerers most often adult males
RISK FACTORS
• Conflict
• Stress
• Anxiety
• Depression
• Secondary gain
• Psychiatric syndrome
PATHOPHYSIOLOGY
• Acuity and visual field decrease
• Ocular motility
– Spasm of near reflex
– Convergence insufficiency
– Horizontal or vertical gaze paralysis
– Nystagmus
Horizontal, vertical, torsional
Random saccadic bursts
• Pupil size and reactivity
– Dilation and tonicity
• Eyelid position
– Pseudoptosis and blepharospasm
• Corneal and facial sensation
– Relative anesthesia or hypersensitivity
ETIOLOGY
See Risk Factors 2A
COMMONLY ASSOCIATED CONDITIONS
• See Risk Factors
• Psychiatric syndromes affect approximately one-third patients 2A, 3A
– Conversion reaction
– Depression
– Hypochondriasis
– Body dysmorphic disorder
– Somatization disorder
DIAGNOSIS
HISTORY
• Nature of complaint
• Degree of disability
• Affect
• Attitude toward care givers
• Degree of concern toward problem
• Determine motivation for symptoms
PHYSICAL EXAM
• Loss of visual acuity
– Binocular or monocular
• Loss of visual field
– Nonspecific constriction most common
– Central scotomas
– All types of hemianopias
• Monocular diplopia
– Not explained by refraction, corneal, or lenticular pathology
– Images are often equal and separate
• Voluntary nystagmus
– Rapid to-and-fro movements only able to be sustained for seconds without rest
– Able to be produced by 5–8% of normal population and may be familial
– Usually horizontal, but vertical and torsional reported
– Eyelids open or closed
– Rarely monocular
– May occur during normal visual tracking
– Resemble ocular flutter or opsoclonus but no neurologic pathology
• Convergence loss
– Often seen with loss of accommodation
• Spasm of the near reflex
– Convergence, accommodation, and miosis
– Limitation of abduction
DIAGNOSTIC TESTS & INTERPRETATION
Lab
• Acuity
– Acuity starting with smallest line
– Near acuity
– OKN Drum
– Mirror test
• Eyes follow tilting mirror
– Prism dissociation test
• Visual field
– Goldmann or Tangent Screen
– Crossing Isopters
– Target Visual Field 4A
– Automated
– Observation
Ambulatory ability not consistent with test results
Imaging
Initial approach
• Indicated when acuity not correctable or visual field loss is reproducible
• MRI
Follow-up & special considerations
• Image areas responsible for symptoms
• Functional overlay
– Present in almost 10% 5A, 6A
– Symptoms out of proportion to organic pathology
Diagnostic Procedures/Other
• Multi focal ERG 1A
• Visual Evoked Potential 6A
DIFFERENTIAL DIAGNOSIS
• Always consider early or subtle organic disease
– Macular dystrophies
– Retinopathy
– Acute zonal occult outer retinopathy
– Leber’s hereditary optic neuropathy
– Optic neuritis
– Paraneoplastic optic neuropathy
– Occipital epilepsy
– Atypical migraine aura
– Infarction, inflammation, or mass lesion
TREATMENT
ADDITIONAL TREATMENT
General Measures
• Reassurance and compassion
• Review exam in a positive manner with patient and family
– Do not confront suspected malingerer
Issues for Referral
Suspicion of suicide or physical harm to patient or others
Additional Therapies
Psychotherapy
ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
Reevaluate symptoms if persistent or increasing
PROGNOSIS
Resolution occurs in over 50%
REFERENCES
1. Chen CS, Lee AW, Karagiannis A, et al. Practical clinical approaches to functional visual loss. J Clin Neurosci 2005;14(1):1–7.
2. Lim SU, Siatkowski RM, Farris BK. Functional visual loss in adults and children. Opthalmology 2005;112(10):1821–1828.
3. Taich A, Crowe S, Kosmorsky GS, et al. Prevalence of psychosocial disturbances in children with nonorganic visual loss. J AAPOS 2004;8(5):457–461.
4. Hsu JL, Harley CM, Foroozam R. Target visual field: A technique to rapidly demonstrate nonorganic visual field constriction. Arch Opthalmol 2010;128(9):1220–1222.
5. Digre KB, Nakamato BK, Warner JEA, Langeberg WJ, Baggaley SK, Katz BJ: A comparison of idiopathic intracranial hypertension with and without papilledema. Headache 2009;49:185–193.
6. Suppiej A, Gaspa G, Cappellari A, et al. The role of visual evoked potentials in the differential diagnosis of functional visual loss and optic neuritis in children. J Child Neurol 2011;26(1):58–64.
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