Abstract
Purpose: :
The aim of this study was to study blinking parameters using a videonystagmography device, in order to determine objectively disability, and to assess the efficiency of botulinum toxin injection in patients with essential blepharospasm.
Methods: :
Blinking was studied using the features of pupillary occlusion (PO) as recorded on a videonystagmography device. In 23 patients presenting with essential blepharospasm, we studied the frequency, the percentage and the mean duration of PO, and the longest PO in a 5min test time. Patients were tested prior to botulinum toxin injection, and respectively 1 month and 3 months after injection. PO of less than 0.3 s and more than 0.3 s were studied apart.
Results: :
At 1 month after injection, botulinum toxin significantly influenced PO higher than 0.3 s, both in frequency (9.6/min ± 8.2 on Day0 and 4.7/min ± 7.2 on Month1 (p=0.004)), and in mean duration (0.95 s ± 0,84 on Day0 and 0.58 s ± 0,34 on Month1 (p=0.03)). On the other hand we found no significant effect on PO of less than 0.3 s, both in frequency (32.4/min ± 28.4 on Day0 and 31.3/min ± 29.0 on Month1 (p=0.7)) and in mean duration (0.16 s ± 0.04 at Day0 and 0.15 s ± 0.03 at Month1 (p=0.4)). Botulinum toxin significantly influenced also the mean duration of the longest PO (6,44 s ± 9.4 on Day0 and 1.55 s ± 1.9 on Month1 (p=0.004)) as well as the percentage of PO (29,95% ± 24.6 on Day0 and 13.44% ± 11.1 on Month1 (p=0.003)).
Conclusions: :
PO can be used as the indirect sign of blinking. Videonystagmography provides a real-time result, and could be used to objectively evaluate the effect of botulinum toxin treatment in essential blepharospasm patients.
Keywords: eyelid • pathology techniques • visual impairment: neuro-ophthalmological disease