More information about text formats
I agree with Dhonde et al. (1) that a pair of humble 20 dioptre lens spectacle is often sufficient and less cumbersome than Frenzel glasses for routine bedside use at acute neurology and emergency wards. I have been using such glasses for more than 10 years to help distinguish peripheral from central nystagmus. Video 1 shows a lady with acute left vestibular neuronitis. Her right beating primary position nystagmus is more pronounced when visual fixation is removed using above-mentioned spectacles. Another trick is to ask the patient to gently shut the eye lids, Video 2. Some patients, like this man with acute left vestibular neuronitis, do have thin enough eyelids to discern the enhancement of nystagmus from the removal of visual fixation.
1. Dhonde P, Khadilkar S. Frenzel glasses: an affordable alternative. Pract Neurol. 2020 Dec;20(6):504.
Legend for video:
a. VIDEO1-Peripheral nystagmus, more obvious with removal of visual fixation using modified Frenzel glasses: https://cloud.degoo.com/share/IKZ3Xj6YlnbMZ1Xe16ui0A
b. VIDEO2-Peripheral nystagmus, worse on eye closure: https://cloud.degoo.com/share/FyVfA144V6oHsULRgUOuIQ