Objectives: Apply a videonystagmography (VNG) device to study indirectly blinking in patients with essential blepharospasm.
Patients and methods: A VNG device was used to study the pupillary occlusion. It was recorded and analyzed as indirect parameters of blinking in 23 essential blepharospasm on day 0, month 1, and month 3 following botulinum toxin injection using VNG.
Results: Botulinum toxin significantly reduced pupillary occlusions (PO) frequency (9.6 PO/min on D0 and 4.7 PO/min on M1 (p = 0.004), and average PO time (0.95 sec on D0 and 0.58 sec on M1 (p = 0.03) for PO higher than 0.3 sec. On the other hand, it does not have any action on frequency (32.4 PO/min on D0 and 31.3 PO/min on M1 (p = 0.7) and average PO time (0.16 sec on D0 and 0.15 sec on M1 (p = 0.4) of PO lower than 0.3 sec.
Conclusion: Video acquisition computer-assisted makes it possible to measure blinking parameters indirectly in real time and to assess essential blepharospasm objectively. The protocol analysis of PO is attractive for indirect analysis of blinking.