The purpose of this study was to assess blepharospasm patients regarding the effect of botulinum toxin in ocular surface parameters. A prospective study was performed in blepharospasm patients treated with onabotulinumtoxinA. A smartphone (iPhone 6S, Apple) and custom-made software were used to record the eyelid movements for 3 minutes in a standardized manner. Optical coherence tomography of the tear meniscus was used to assess the tear meniscus area. Tear break-up time and the Ocular Surface Disease Index questionnaire were also evaluated. Patients were assessed before and 15 days after botulinum toxin injections. Forty eyes of 20 patients were evaluated. The frequency of the spontaneous eyelid movements was significantly reduced after treatment (23.18 ± 12.85 movements/min vs. 9.29 ± 6.87 movements/min; p < 0.0001). Significant increases in the tear meniscus area (0.020 ± 0.015 mm 2 vs. 0.057 ± 0.104 mm 2 ; p = 0.01) and in break-up time (4.2 ± 1.2 seconds vs. 5.1 ± 1.3 seconds; p = 0.03) were observed 15 days after treatment. A significant reduction in the Ocular Surface Disease Index (59.05 ± 19.04 vs. 21.2 ± 19.5; p < 0.0001) was also observed. Significant changes in the tear meniscus area, break-up time, and Ocular Surface Disease Index after treatment reflect the effect of botulinum toxin on the lacrimal pump and in the improvement of dry eye symptoms. Reduction of eyelid spasms after treatment in blepharospasm patients was demonstrated using a smartphone and custom-made software. Thus, beyond relieving eyelid spasms, botulinum toxin injections were associated with subjective and objective improvement of dry eye parameters in patients with blepharospasm.