Smartphone and custom-made software to assess the effect of botulinum toxin in essential blepharospasm: Initial results.

[BACKGROUND AND PURPOSE] It is challenging to assess essential blepharospasm (EB) patients objectively because they exhibit chaotic patterns of abnormal eyelid movements. Previously employed objective approaches used systems with low levels of accuracy systems or were too complex to be applied in routine clinical practice. We aimed to develop a practical tool using a smartphone camera and custom-made software to objectively assess the therapeutic effects of botulinum toxin in blepharospasm patients.

[METHODS] Thirty-four patients with EB were evaluated before and 15 days after receiving onabotulinumtoxinA injections. The control group was composed of 19 age-matched healthy individuals. A smartphone (iPhone 6 S; Apple) was used to record spontaneous eyelid movements for 3 min, after which eyelid movement frequency was analysed using custom-made software.

[RESULTS] Before treatment, eyelid movement frequency was significantly higher in the EB group (21.55 ± 13.30 movements/min) compared to the control group (8.26 ± 8.89 eyelid movements/min; p < 0.001). The frequency of spontaneous eyelid movements was significantly reduced after treatment in the EB patients (8.46 ± 6.32 eyelid movements/min; p < 0.001). After treatment, no statistically significant difference in eyelid movement rate was observed between the EB patients and the control group (p = 0.32).

[CONCLUSIONS] Assessment of the spontaneous eyelid movements obtained with the smartphone camera and analysed with the custom-made software enabled us to objectively measure the therapeutic effects of botulinum toxin in patients with blepharospasm. Further refinement of this system could enable customized and fine adjustments to botulinum toxin doses based on each patient's needs.