An atypical presentation of functional visual loss: A case report

Binasal congruous hemianopia secondary to functional visual loss: A case report

INTRODUCTION

To describe an unusual case of binasal congruous hemianopia secondary to functional visual loss (FVL).

PATIENT CONCERNS

A 24 year-old male was referred originally by his optician at the Emergency Eye Department of the Leicester Royal Infirmary in October 2018 with visual field changes affecting the nasal field of vision in both eyes on routine eye examination. The patient reported ongoing headaches over the last 6 weeks to 8 weeks associated with simultaneous peripheral visual field changes. He also reported rapid loss of weight over the same period of time.

DIAGNOSIS

Binasal congruous hemianopia secondary to FVL.

INTERVENTIONS

Full past medical and ocular history was obtained. The patient underwent full ophthalmic examination including dilated fundoscopy. Visual acuity was recorded with Snellen Chart. Color vision was assessed with Ishihara plates. Peripheral vision was assessed with both Humphrey visual fields and Goldmann visual fields. Optical coherence tomography of the macula and discs was also performed. Neuroimaging investigations included Computerized Tomography (CT) and Magnetic Resonance Imaging (MRI) of the Brain. Electrophysiology investigations included Electroretinogram and visual evoked potentials. Patient was also tested for syphilis.

OUTCOMES

Humphrey visual fields and Goldmann visual fields confirmed the presence of complete binasal field defects. Optical coherence tomography, electroretinogram, visual evoked potentials, CT, MRI were all unremarkable. Ocular examination was normal. Finally, syphilis serology was negative. After 1 year of follow-up, the visual field changes have remained the same.

CONCLUSION

To the best of our knowledge, this is the fourth case described in the literature with complete congruous binasal hemianopia due to FVL. We advocate thorough investigations with multimodal imaging of the fundus, neuroimaging and syphilis serology to exclude serious organic causes for binasal field defects prior to labeling such a field defect functional. Such patients may benefit from neuropsychological input to understand the psychological factors that may be contributing to the symptoms.

Idiopathic binasal hemianopia: case report and literature review

A 56-year-old lady was referred for complete binasal hemianopia noticed during routine glaucoma screening. On examination the patient was asymptomatic, there were no ophthalmic causes explaining her visual field defect and further neurologic investigation was normal. Binasal hemianopia is an uncommon finding that is usually associated to intraocular conditions, but may rarely be caused by neurologic diseases. The Authors also review the current ophthalmic literature about binasal hemianopia in patients with otherwise complete neurologic and ophthalmic investigation (idiopathic binasal hemianopia).

Pattern-Reversal Visual Evoked Potential on Smart Glasses

OBJECTIVE

This paper presents an integrated device, based on smart glasses, for the pattern-reversal visual evoked potential (PR-VEP) clinical test.

METHODS

Smart glasses are used to generate the checkerboard changing pattern, with its related red fixation point through an Android application. Electroencephalographic signals, for monitoring the stimulus generated by PR-VEP, were amplified close to the scalp and then transmitted wirelessly to a PC. A MATLAB real-time algorithm processed the incoming signals to extract the final PR-VEP signal.

METHODS

In total, 40 eyes (from 20 subjects, 12 males and 8 females between 24 and 28 years old) were tested and results were compared, with a commercial device for VEP clinical exam, to test the reproducibility and the efficacy of the proposed solution.

RESULTS

PR-VEPs generated by smart glasses showed typical triphasic waveforms: We observed promising results and components in moderate agreement with those obtained using commercial PR-VEP recorder, with potential for improvements after further refinement works.

SIGNIFICANCE

The proposed device leads the way for a portable and low-cost solution.