A case of functional visual loss diagnosed through bilateral randomized visual field testing with a trick method

Area of Science:

• Ophthalmology
• Neuroscience

Background:

• Functional visual loss (FVL) presents diagnostic challenges, often mimicking organic visual field defects.
• A 27-year-old male presented with visual field abnormalities post-trauma, initially suspected as traumatic optic neuropathy.

Observation:

• Despite normal initial neurological imaging and pupillary responses, the patient's visual acuity and critical flicker frequency declined.
• Goldmann perimetry revealed progressive visual field constriction and a spiral pattern, inconsistent with organic pathology.

Findings:

• Bilateral randomized visual field testing using the Imo vifa with a trick method successfully identified left homonymous hemianopsias and concentric visual field constriction.
• These findings were not attributable to any identifiable organic disease, supporting a diagnosis of FVL.

Implications:

• The described trick method of bilateral randomized visual field testing is a valuable tool for diagnosing FVL.
• This approach aids in differentiating functional from organic visual impairments, guiding appropriate patient management.