• Written By:

    Aubrey Gilbert, MD

     

    Neuro-Ophthalmology

    Establishing the diagnosis

    Non-organic visual loss (NOVL) is defined as a disturbance in any aspect of vision with exam findings that do not support an underlying organic etiology. This phenomenon has also been previously referred to by many terms, including “hysterical,” “functional,” “factitious,” “fictitious,” or “psychogenic” visual loss. Lessell suggests that “non-organic” is the most appropriate label for ophthalmologists to use.1 NOVL can be challenging to identify and manage, and it is of particular importance to be aware of the diagnosis in children because multiple studies have reported that there can be an association of NOVL with psychosocial stressors and/or other psychiatric diagnoses in the pediatric population.2 Familiarity with some of the basic techniques for diagnosing NOVL may preempt the need for extensive and expensive work-ups. It is also very important to remember that NOVL is a diagnosis of exclusion and, in many cases, patients with NOVL may also have an actual underlying organic problem that is masked by their other complaints. Knowing some of the recommended approaches to diagnosing and managing pediatric NOVL can foster trust with patients and parents and can speed recovery.

    Etiology

    It has been estimated that anywhere from 1% to 5% of general ophthalmology patients may present with NOVL. In school-age children, the incidence has been reported as 1.75%.3,4 Van Balen and Slijper (1978) argue that NOVL is so common in the pediatric population that it should actually be considered a variant of normal in children.5 NOVL can occur at any verbal age but it is most common in pre-pubertal and pubertal-aged children from approximately 8 to 14 years old.6-9 Most studies on NOVL report that a large majority of patients are female and that NOVL also tends to occur at a younger average age in girls. One report found that for boys, the mean age of presentation was 10 years old and for girls it was 9.4 years old,10 while others have shown an even bigger difference, with a mean age of onset of 10 years old for boys and 8 years old for girls.7-9

    Taich et al. (2004) presented a case series looking at the prevalence of psychosocial stressors in 71 consecutive pediatric patients with NOVL and found that 31% had significant home and/or school stress, such as academic difficulties, trouble adjusting to a new environment, separation from parents, and even physical and/or sexual abuse.2 Bain et al. (2000) also found concomitant social problems at home or school in 60% of children diagnosed with NOVL.9 Catalano et al. (1986) corroborates, reporting that 39% of their NOVL patients had difficulty in school and 35% had family problems.7 Yasuna (1963) found that children with NOVL were more frequently from families with lower socioeconomic status, although later studies have not definitively supported this finding.6 A review by Moore et al. (2012) indicated that most patients did not have any specific underlying defined triggering event but rather often described having generalized stress.11

    Finally, Clarke et al. (1996) also reported that pediatric patients with NOVL tended to be of normal or above normal intelligence and also slightly overweight, although this latter characteristic is not mentioned in most of the papers on the topic.10 Of the patients reported by Taich, 26.7% had previously been given a psychiatric diagnosis; it was most commonly associated with anxiety, depression or attention deficit hyperactivity disorder.2 The single factor underlying NOVL in nearly a quarter of these patients was found to be a desire to obtain eyeglasses.

    Presentation

    While pediatric patients with NOVL can present with almost any visual complaint, Clarke et al. (1996) reported that most NOVL patients fell into one of three categories: (1) decreased visual acuity or color vision in one or both eyes, (2) diplopia, or (3) complaint of seeing lines, spots ,or illusory movement or having pain with visual tasks.10 Bain et al. (2000) reported that 93% of patients with NOVL complained of reduced or blurred vision.9 The second most common complaint in pediatric NOVL is visual field loss, which has been reported to occur in around 48% of patients.4 Most children report bilateral, symmetric symptoms. The duration is variable with a median of 2 months and a range from 1 day to 3 years.7,9 Associated nonvisual symptoms such as headache, periorbital pain, and photophobia may be reported.9 The mean presenting visual acuity was found to be 20/50 in one series of 52 children with NOVL.3 Although any visual acuity may be found, it usually ranges between 20/30 and 20/100.7

    Diagnosis

    The evaluation of patients with suspected NOVL should actually begin in the waiting room. Their appearance and demeanor as well as their ability to play, walk, navigate, and focus on people and objects can be assessed even before they enter the examination room. After that, the specific evaluation can be tailored to the reported visual complaint and degree of impairment. Doctors must be cautious to avoid making patients feel they are being directly challenged. Being comfortable with a few useful techniques will help avoid arousing suspicion in patients when they are being tested. Often it is easier to demonstrate non-organic visual loss in children than in adults, because children tend to be more suggestible. Some good techniques for pediatric patients include placing “magic” saline eye drops into the eye or eyes or holding a “magic” plano lens in front of the eye or eyes and explaining that vision will be temporarily improved by these measures. The use of a fogging lens over the good eye and testing of stereopsis, optokinetic response, and tangent fields are also simple ways to determine non-organic visual loss. For challenging cases, some authors have reported on the use of visual evoked potentials and video pupillography during automated perimetry to aid in diagnosis, although these are unnecessary in most cases and may be difficult to apply in many children.12-14 It should be cautioned that a patient can voluntarily alter the measurement of visual evoked potentials by purposefully defocusing during testing.15,16 More detailed discussion of specific options for demonstrating NOVL tailored to a patient’s specific complaint can be found in review articles by Moore et al. (2012) and Chen et al. (2007).11,17

    Natural History

    The vast majority of pediatric patients with NOVL improve spontaneously. In 2000, Bain reported that  the patients evaluated all resolved with reassurance.9 Ninety-three percent of children diagnosed with NOVL by Toldo et al. (2010) had complete resolution of their symptoms and 85% of these resolved within 1 year.4 Two-thirds of patients in a paper by Catalano et al. (1986) had resolution of symptoms by two months after onset and the report indicates that recurrence of NOVL is rare.7

    Patient management: treatment and follow-up

    Treatment

    All authors seem to agree that reassurance is the mainstay of treatment for pediatric non-organic visual loss.5,6,9,18 Van Balen and Slijper (1978) found that parents tend to respond to the diagnosis of NOVL in one of two ways: either with a knowing smile or with disbelief, the latter being more difficult to manage.5 They suggest demonstrating to the unconvinced parent how it was determined that the visual loss is non-organic; for example, letting the child read the eye chart through a plano lens was found to improve their child’s vision.

    The establishment of a good rapport will make patients more likely to respond favorably to suggestion. Physicians can help support patients and parents by explaining that no serious disease exists and by emphasizing positive findings with which the patient is likely to agree. One can comment on the health of specific parts of the eye.18 It is important to reaffirm that the vision is likely to recover to give patients “a way out” of their vision loss. Physicians can explain that they have seen other patients with similar problems before and that those patients have had full recoveries.

    There is not felt to be a role for pharmacological treatment in NOVL although Shindler et al. (2004) suggest that particularly suggestible pediatric patients may benefit from use of artificial tears.18

    Organic visual loss in the setting of non-organic visual loss

    It has been estimated that as many as half of all patients with NOVL may have an identifiable underlying organic problem.19 Non-organic visual loss can make it challenging to identify these issues. In one report by Lim et al. (2005), commonalities among the three patients described who were originally diagnosed with NOVL but later found to have organic disease included inconsistent responses during examination that did not completely account for the abnormal finding, and lack of demonstration of normal visual function.20 A central scotoma was noted on visual field testing of one of these patients, and when this is seen, organic pathology should be strongly suspected. The more common visual field findings in NOVL are spiral or tunnel visual fields. The high incidence of concurrence of organic disease reinforces the importance of maintaining NOVL as a diagnosis of exclusion. Additionally, although the proportion of children diagnosed with NOVL who have a history of abuse is small, Moore et al. (2012) suggest that because of the graveness of such a situation, doctors should consider this possibility in the evaluation and should attempt to have a frank discussion with the patient without parents present and also with each individual parent alone.11 They also discuss whether a diagnosis of NOVL merits a referral for psychiatric evaluation. In the majority of cases, especially for patients with younger onset and lack of any prior psychiatric history, this does not seem to be necessary. However, in the pediatric NOVL population evaluated by Taich et al. (2004), nearly a third of patients reportedly had underlying psychiatric illness, so consideration of psychiatric pathology in evaluating NOVL has been recommended.2 Many other papers do not support this high incidence of psychiatric comorbidity and argue against a need for referral for most pediatric NOVL patients.7,9,10

    Summary

    Non-organic visual loss is a relatively common phenomenon in the pediatric population. There are many strategies and techniques for identifying NOVL. In children, it is of particular importance to be aware of the diagnosis, because there can be an association between NOVL and psychosocial stressors including abuse and, possibly, psychiatric comorbidity. Familiarity with some of the basic techniques for diagnosing NOVL may preempt the need for extensive and expensive work-ups, but it is also very important to maintain NOVL as a diagnosis of exclusion because some patients may have underlying organic pathology. The diagnosis of NOVL should only be confirmed when the vision is normal, which may take time and more than one follow-up visit. Most patients with NOVL improve with reassurance alone, and this is the mainstay of treatment.

    References

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