Voluntary Flutter Presenting During Ophthalmoscopy: A Case Report.

Area of Science:

• Ophthalmology
• Neuroscience
• Autism Spectrum Disorder Research

Background:

• Voluntary flutter is a rare, conjugate saccadic eye oscillation seen in healthy individuals.
• It is distinct from pathological nystagmus, which has various causes and onset times.
• This condition is often associated with convergence but can manifest atypically.

Observation:

• An unusual case of voluntary flutter presented in a 20-year-old male with autism spectrum disorder during an eye exam.
• The patient exhibited normal visual acuity, refraction, and ocular motor balance.
• Fine, intermittent eye tremors were observed, particularly during convergence, upon request.

Findings:

• Eye movements were recorded using an EyeLink 1000 eye tracker at 1,000 Hz.
• The voluntary flutter consisted of horizontal saccadic oscillations with an average frequency of 13 Hz and amplitude of ~8°.
• The oscillations reduced in frequency and amplitude over time and could be sustained with effort.

Implications:

• The study suggests that discomfort during close examination might trigger voluntary flutter.
• Voluntary flutter can be a crucial differential diagnosis for apparent new-onset nystagmus without other neurological signs.
• Understanding this phenomenon aids in accurate diagnosis and patient management, especially in neurodevelopmental contexts.