Purpose: To evaluate ocular surface changes secondary to periocular botulinum toxin A injection in patients with essential blepharospasm.
Methods: Thirteen eyes of 13 patients with essential blepharospasm who underwent periocular botulinum toxin A injection were included in this prospective study. Patients were evaluated prior to and at 2-week and 1-, 3-, and 6-month time points following injections. Ocular surface tests were carried out in the order of tear break-up time (TBUT), lissamine green (LG) staining, Schirmer I test with anesthesia, and ocular surface disease index (OSDI) questionnaire for all patients. The Friedman test with Conover post hoc method was used for statistical comparisons of values at different time points.
Results: The TBUT was found to be increased at 1 month after the injection (8.5 ± 2.1; p = 0.018) and decreased below baseline levels (6.4 ± 2.1) at the 6-month visit (5.7 ± 2.0; p = 0.018). None of the Schirmer test values at follow-up visits were significantly different as compared to baseline levels (11.3 ± 5.5), although the 2-week measurement (14.3 ± 5.6) was significantly higher as compared to that at the 6-month follow-up visit (9.6 ± 4.9; p = 0.034). There was also a significant decrease in LG staining scores at 2-week (0.6 ± 0.4; p = 0.012) and 1-month (0.6 ± 0.4; p = 0.012) time points compared to the baseline levels (1.1 ± 0.6). The OSDI scores improved at 2-week (5.4 ± 6.8; p<0.001), 1-month (3.2 ± 5.1; p<0.001), 3-month (2.5 ± 4.4; p<0.001), and 6-month (5.5 ± 5.4; p<0.001) time points as compared to baseline levels (11.6 ± 8.5).
Conclusions: Botulinum toxin A injection appears to have a positive but temporary effect on ocular surface parameters in patients with blepharospasm.