When is a malingerer not a malingerer? A case study report

Paper title: Navigating the differential diagnoses of possible malingerers within the paediatric population

Author: Madeline T Baker

1. School of Medicine, Deakin University, Victoria, Australia.

Date: May 2024

Reference: Baker MT. Navigating the differential diagnoses of possible malingerers within the paediatric population. Clin Exp Optom. 2024 May;107(4):475-477 [Link to open access paper]

This article outlines a case report of a child with a history of low hyperopia who presents for an eye examination with reduced vision. The 8-yr old girl had broken spectacles but had also found her +0.25DS prescription was ineffective. The patient was not forthcoming with information during the appointment. However, history-taking revealed no family history of strabismus and with no underlying health issues suspected, the initial assessment suggested an up-to-date refraction was needed.

A comprehensive eye examination was performed which revealed the following. 

• A small right eye ptosis which worsened during the consultation
• Diplopia on abduction both eyes for all lateral gazes despite no over- or under-action in the cardinal positions or alignment issues found with cover testing.
• Intermittent suppression of the right eye at both 30cm and 6m and poor stereoacuity at 250s of arc.
• The patient also failed to correctly identify a number of Ishihara colour vision test plates but was able to trace a snake pattern for one which led to a suspicion of malingering.
• Dry retinoscopy of R (OD) +0.25/-0.25×180 and L (OS) +0.50/-0.25×10, confirmed on cycloplegic retinoscopy with best corrected acuity of only 6/9.5 (20/32) in each eye. There was no improvement in visual acuity when measured at 3m. However, the patient correctly stated she saw no difference with a plano lens she was told ‘would help.’ 
• No evidence of a relative afferent pupillary defect was found and a dilated fundus examination was unremarkable. 
• Generalised visual field loss was discovered, with a diffuse cloverleaf pattern seen in both eyes. 
• A potential accommodative infacility was suspected when the patient was unable to clear ±2.00D. However, the near points of convergence and accommodative posture were within expected values and the ratio of accommodative convergence per dioptre of accommodation was relatively flat for both plus and minus powered lenses.

Further careful questioning of the girl’s father revealed the patient had suffered physical harm at school, with confluent bruising across her back. The discrepancy between the subjective and objective clinical findings and the extra information gained from the father led to a diagnosis of Streff syndrome.

Streff syndrome is an involuntary, psychogenic condition typically seen in children aged 6-12yrs and is twice as prevalent in girls. It is characterised by reduced visual acuity (No better than 6/7.5 or 20/25), near-point stress, decreased ocular function, low plus refractive error (between plano and +1.00) which does not improve acuity, and reduced stereopsis, colour vision and / or restricted visual fields. It is often secondary to accommodative or vergence disorder and can be described as a condition which gives a misrepresentation of the visual environment where psychological stress has resulted in altered functional vision.

A discrepancy between subjective and objective findings while finding no likely underlying ocular or neurological aetiology initially led to suspecting malingering in this case, however the diagnosis was Streff syndrome. This condition has a strong association with external stress. The psychological cause needs to be addressed by working with other healthcare professionals such as doctors, psychologists, paediatricians and social workers to provide a holistic and collaborative approach for treatment.

Reduced acuity, eyestrain symptoms and/or binocular vision difficulties may be encountered in children with pre-myopia or myopia progression - this case report helps to highlight the importance of careful examination for all children. In childhood eye care and myopic management, it is crucial to:

• undertake a thorough history-taking
• understand the child’s environment at school and at home
• involve the parents or guardians where possible for further context or clarification, where children are uncommunicative with practitioners
• perform examinations and assessments as objectively as possible
• give full consideration to differential diagnoses, particularly with evidence of visual function loss
• refer the patient in a timely manner to other healthcare professionals if appropriate
• follow-up at appropriate intervals to monitor ocular and general health

This ensures all children receive the appropriate attention, regardless of their prescription or how 'genuine' or 'real' their symptoms may be.

To help differentiate from a malingering diagnosis, the patient in this case report was told a plano lens ‘would help’ to see the chart better. The patient correctly noticed no difference with this lens in place, but due to their visual acuity they may have struggled to perceive a difference.

Alternative acuity-based tests may be useful in cases such as this. When the acuity is near to normal, incrementally reducing a high-powered lens and checking the new visual acuity in stages may help confirm when a patient is reaching an expected vision level.

Title: Navigating the differential diagnoses of possible malingerers within the paediatric population

Authors: Madeline T Baker.  No abstract available for this article. [Link to open access paper]