Functional vision loss:

How do I manage functional visual loss

Functional visual loss is a subtype of functional neurological disorder (FND) and is a common cause of visual impairment seen in both general and neuro-ophthalmological practice. Ophthalmologists can generally diagnose functional visual loss reasonably confidently but often find it harder to know what to say to the patient, how to approach, or even whether to attempt, treatment. There is little evidence-based treatment despite studies showing up to 60% of adults having impactful symptoms on long-term follow-up. The last 20 years has seen large changes in how we understand, approach, and manage FND more widely. In this article, we set out our practical approach to managing functional visual loss which includes : 1) Make a positive diagnosis based on investigations that demonstrate normal vision in the presence of subjectively impaired vision, not just because tests or ocular exam is normal; 2) Explain and label the condition with an emphasis on these positive diagnostic features, not reassurance; 3) Consider eye or brain comorbidities such as migraine, idiopathic intracranial hypertension or amblyopia; 4) Consider working with an orthoptist using diagnostic tests in a positive way to highlight the possibility of better vision; 5) Develop simple treatment strategies for photophobia; 6) Consider psychological factors and comorbidity as part of assessment and therapy, but keep a broader view of aetiology and don't use this to make a diagnosis; 7) Other treatment modalities including hypnotherapy, transcranial magnetic stimulation and more advanced forms of visual feedback are promising candidates for functional visual loss treatment in the future.

Functional vision disorder: a review of diagnosis, management and costs

Functional vision disorder (FVD) is a relatively common diagnosis in ophthalmic practice which can be difficult to make because of clinician's apprehension to miss organic pathology. We review the diagnostic approach to patients with FVD, organic mimics of FVD, its diagnostic and management strategies and associated cost burden. Patients with FVD typically present with visual acuity and/or field loss. Diagnostic work-up should include patient observation, detailed history, pupillary examination, dilated ophthalmoscopy, visual field testing and ganglion cell analysis of the macular complex. Most common organic mimickers of FVD are amblyopia, cortical blindness, retrobulbar optic neuritis, cone dystrophy and chiasmal tumours; however, all could be ruled out by structured diagnostic approach. For patients with unilateral visual loss, bottom-up refraction, fogging of the well-seeing eye in the phoropter, convex lens and base-down prism tests could aid in diagnosis. For patients claiming binocular vision loss, checking for eye movement during the mirror test or nystagmus elicited by an optokinetic drum can be helpful. Effective management of FVD involves reassurance, stress reduction and, if agreed on, management of comorbid anxiety and/or depression. The social cost of FVD is predominately economic as patients typically meet several healthcare providers over multiple visits and often undergo several neuroimaging studies before neuro-ophthalmology referral. Further, inappropriate granting of disability benefits confers additional stigma to patients with organic vision loss.

Association of vitamins with hearing loss, vision disorder and sleep problem in the US general population

Based on nationally representative samples from US, we aimed to assess the associations of vitamins with hearing loss, vision disorder and sleep problem. A total of 25,312, 8425 and 24,234 participants were included in this study to investigate the relationship of vitamins with hearing loss, vision disorder and sleep problem from National Health and Nutrition Examination Survey, respectively. Vitamins including niacin, folic acid, vitamin B6, A, C, E and carotenoids were considered in our study. Logistic regression models were used to assess the associations between all included dietary vitamin intake concentrations and the prevalence of specific outcomes. Increased lycopene (odds ratio [OR]: 0.904, 95% confidence interval [CI]: 0.829-0.985) intake was associated with a deceased prevalence of hearing loss. Higher dietary intake of folic acid (OR: 0.637, 95% CI: 0.443-0.904), vitamin B6 (0.667, 0.465-0.947), alpha-carotene (0.695, 0.494-0.968), beta-carotene (0.703, 0.505-0.969) and lutein + zeaxanthin (0.640, 0.455-0.892) were associated with a decreased prevalence of vision disorder. The inversely associations of sleeping problem with niacin (OR: 0.902, 95% CI: 0.826-0.985), folic acid (0.882, 0.811-0.959), vitamin B6 (0.892, 0.818-0.973), vitamin C (0.908, 0.835-0.987), vitamin E (0.885, 0.813-0.963) and lycopene (0.919, 0.845-0.998) were also observed. Our findings provide evidence that increased specific vitamin intake is associated with decreased prevalence of hearing loss, vision disorder and sleep problem.

Management of Functional Vision Disorders

PURPOSE OF REVIEW

The purpose of this review is to summarize current approaches to management of functional vision disorder (FVD).

RECENT FINDINGS

Several retrospective studies of FVD in both adults and children have shed light on the range of outcomes and the prevalence of psychosocial stressors among FVD patients. While the first line of treatment for FVD is reassurance and education, recent case reports highlight the use of additional treatment modalities including psychotherapy, hypnosis, and transcranial magnetic stimulation in specific cases. Although the epidemiology and diagnosis of functional vision disorder are well described, there is limited evidence supporting treatment modalities. Nevertheless, the majority of patients improve with conservative management including reassurance, education, and appropriate follow-up. Additional approaches such as mental health care referral can be considered in refractory cases.

Functional vision disorders in adults: a paradigm and nomenclature shift for ophthalmology

Vision loss with clinical findings that are incompatible with the symptoms and recognized neurological or ophthalmic conditions is a common presentation of patients to neurologists, ophthalmologists, and neuro-ophthalmologists. The accepted terminology to describe such patients has evolved over time, including functional visual disorder (FVD), non-organic vision loss, non-physiologic vision loss, functional vision loss, psychogenic, psychosomatic, and medically unexplained visual loss. Likewise, attitudes and recommended management options have changed over the years in the fields of psychiatry and neurology. FVD is a diagnosis of inclusion, and it is critical that the diagnosis be made and delivered efficiently and effectively to reduce patient and physician duress. We review the current Diagnostic and Statistical Manual (DSM V) terminology and the prior literature on FVD and describe how the approaches to diagnosis and management have changed. We provide recommendations on the appropriate techniques and diagnostic approach for patients with FVD. We also propose a protocol for consistent and standardized discussion with the patient of the diagnosis of FVD. We believe that the adoption of FVD as both a paradigm and nomenclature shift in ophthalmology will improve patient care.

Glucose hypometabolism in the visual cortex proportional to disease severity in patients with essential blepharospasm

Essential blepharospasm (EB) causes difficulty in eyelid opening because of involuntary movements of the orbicularis oculi muscle. Patients with EB have functional visual loss due to sustained eyelid closure. We examined cerebral glucose metabolism in 39 patients with EB (12 men and 27 women; mean age, 52.1 years) by using positron emission tomography with ¹⁸F-fluorodeoxyglucose. Forty-eight eye open healthy subjects and 48 eye close healthy subjects served as controls. We analyzed and compared the data between the patients and controls by using both statistical parametric mapping (SPM) and regions of interest (ROIs). We defined ROIs on both sides of the posterior striate cortex, anterior striate cortex, extrastriate cortex, and thalamus. In SPM analysis, glucose hypometabolism were observed in both sides of the extrastriate cortex compared to eye open controls but not to eye close controls. We also observed a significant negative correlation between the Jankovic Rating Scale (JRS) sum score and relative glucose metabolism level in the striate cortex of these patients. ROI analysis, a significant correlation was observed between the JRS sum score and glucose metabolism level in the posterior (right: r = −0.53, P = .0005; left: r = −0.65, P = .00001) and anterior (right: r = −0.33, P = .04; left: r = −0.37, P = .02) striate cortices of patients with EB. We surmise that the interruption of visual input cause glucose hypometabolism in the visual cortex of patients with EB.

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Glucose hypometabolism (GM) in the visual cortex in patients with blepharospasm was observed.

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GM level in the visual cortex of blepharospasm was same as that of eye close healthy subjects.

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Negative correlation was observed between severity and GM level in the striate cortex of patients.

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The results of this study reflect the visual symptoms of patients with blepharospasm.

When symptoms don't fit: a case series of conversion disorder in the pediatric otolaryngology practice

Background

Conversion disorder refers to functional bodily impairments that can be precipitated by high stress situations including trauma and surgery. Symptoms of conversion disorder may mimic or complicate otolaryngology diseases in the pediatric population.

Case presentation

In this report, the authors describe 3 cases of conversion disorder that presented to a pediatric otolaryngology-head and neck surgery practice. This report highlights a unique population of patients who have not previously been investigated. The clinical presentation and management of these cases are discussed in detail. Non-organic otolaryngology symptoms of conversion disorder in the pediatric population are reviewed. In addition, we discuss the challenges faced by clinicians in appropriately identifying and treating these patients and present an approach to management of their care.

Conclusion

In this report, the authors highlight the importance of considering psychogenic illnesses in patients with atypical clinical presentations of otolaryngology disorders.

Non-organic Vision Loss in the Afghanistan and Iraq Conflicts

Non-organic visual loss (NOVL), defined as a decrease in visual acuity or field without an identifiable organic cause, can be challenging to diagnose, especially in patients whose NOVL is superimposed on some component of true organic pathology. Exposure to combat puts soldiers at risk of emotional distress and physical trauma, which can contribute to the development of NOVL with conversion disorder or malingering. This case series describes six patients with NOVL who sustained ocular or non-ocular injuries while serving in combat operations in Iraq and Afghanistan, and highlights diagnostic pearls and components of inter-disciplinary management in the unique military context.

Functional and simulated visual loss

Nonorganic visual loss (NOVL) is the cause of a large number of referrals to neurologists and ophthalmologists and is a frequent area of overlap between neurologists, ophthalmologists, and psychiatrists. NOVL is the presence of visual impairment without an organic cause for disease despite a thorough and comprehensive investigation. A diagnosis of NOVL requires both the absence of any findings on examination and proof of the integrity and functioning of the visual system. Although sometimes a challenging diagnosis to make, there are a number of techniques and maneuvers which can be utilized fairly easily, either at the bedside or in the clinic, to help determine if a patient has NOVL. In some instances specialized testing, such as formal visual field testing, optical coherence tomography, visual evoked responses, electroretinogram, and various imaging modalities (magnetic resonance imaging) are performed to help determine if the cause of visual loss is organic or nonorganic. Once a diagnosis of NOVL is made, treatment centers around reassurance of the patient, close follow-up, and, if necessary, referral to a psychiatrist, as these patients may have underlying psychiatric disorders and a preceding strong emotional event leading to the current symptoms, and may be more likely to develop depression and anxiety.

Psychologic treatment of functional neurologic disorders

The management of patients with functional neurologic disorders poses many challenges. Psychologic treatments may well start at the point of delivery of the diagnosis, when careful explanations about the nature of the disorder have to be given to the patient and possibly also relatives/carers. Different conceptual models may assist in explaining the factors underlying the presentation, two of which (functional and dissociative) are briefly outlined here. The challenges for neurologists and psychiatrists of delivering a psychologic formulation as part of the diagnosis delivery are considered, along with the importance of clear communication between professionals involved in the patient's care. Existing literature on treatments incorporating psychologic components suggests that, despite limitations in the study designs and the potential bias in some outcome evaluations, there is evidence to support the use of psychologic interventions for at least some functional neurologic disorders, although larger and better-designed studies are required in this area.

Identification of functional visual field loss by automated static perimetry

PURPOSE

Diagnosis of functional visual field loss, that is, field loss lacking objective corollaries, has long relied on kinetic visual field examinations using tangent screens or manual perimeters. The modern dominance of automated static perimeters requires the formulation of new diagnostic criteria.

METHODS

Retrospective review of automated perimetry records from 36 subjects meeting clinical and tangent screen criteria for functional visual field loss. Thirty-three normal eyes and 57 eyes with true lesions, including optic nerve compression, glaucoma, anterior ischaemic optic neuropathy and vigabatrin toxicity, served as controls.

RESULTS

Standard automated perimetry statistics were unable to reliably discriminate organic versus non-organic visual field loss. Subjective evaluation of perimetric maps indicated that functional fields generally could be identified by the presence of severe and irregular contractions and depressions that did not conform to the visual system's neuro-architecture. Further, functional fields generally presented one or more isolated threshold 'spikes', that is, isolated locations showing much better than average sensitivity. On repeated examinations, threshold spikes always changed locations. Visual evaluation for spikes proved superior to an objective computational algorithm. Fairly reliable objective discrimination of functional fields could be achieved by point-wise correlations of repeated examinations: median intertest correlation coefficients equalled 0.47 compared with 0.81 for true lesions.

CONCLUSION

Functional visual loss can be identified by automated static perimetry. Useful criteria include severe and irregular contractions and depressions, the presence of isolated threshold spikes and poor intertest correlations.