Videonystagmography to assess eyelid dynamic disorders

Area of Science:

• Ophthalmology
• Neurology
• Biomedical Engineering

Background:

• Essential blepharospasm (EB) is a neurological disorder causing involuntary eyelid closure.
• Objective assessment of blinking in EB patients is crucial for treatment evaluation.
• Videonystagmography (VNG) offers a potential method for indirect blinking analysis.

Purpose of the Study:

• To investigate the utility of a VNG device for the indirect assessment of blinking in patients with essential blepharospasm.
• To evaluate the effect of botulinum toxin injections on blinking parameters measured by VNG.

Main Methods:

• A VNG device was employed to record pupillary occlusions (PO) as an indirect measure of blinking.
• 23 patients with essential blepharospasm were studied at baseline (D0), 1 month (M1), and 3 months (M3) post-botulinum toxin injection.
• Analysis focused on PO frequency and duration, differentiating between POs longer and shorter than 0.3 seconds.

Main Results:

• Botulinum toxin significantly decreased the frequency of pupillary occlusions (PO) > 0.3 sec (9.6 to 4.7 PO/min, p=0.004) and their average duration (0.95 to 0.58 sec, p=0.03).
• No significant changes were observed in POs < 0.3 sec in terms of frequency (32.4 to 31.3 PO/min, p=0.7) or duration (0.16 to 0.15 sec, p=0.4).

Conclusions:

• Computer-assisted VNG provides a reliable, real-time method for objective, indirect blinking assessment in essential blepharospasm.
• The analysis of pupillary occlusions using VNG is a promising approach for evaluating treatment efficacy in EB.