Influence of unilateral eyelid spasms and botulinum toxin treatment on intraocular pressure measured by transpalpebral tonometer.

[PURPOSE] Eyelid spasms might be associated with elevated intraocular pressure (IOP) in hemifacial spasm (HFS) patients. IOP assessment using a Goldmann applanation tonometer (GAT) is often compromised by eyelid spasms. This study aimed to assess the effect of HFS on IOP measurements using the transpalpebral tonometer Diaton® before and after treatment with botulinum toxin type A (BTX-A) and compared Diaton® and GAT measurements after treatment with BTX-A.

[METHODS] IOP measurements were obtained with Diaton® in 27 patients with moderate-to-severe HFS before and after treatment with BTX-A. After treatment, the IOP was also measured using GAT and the results were compared with the ones measured with a Diaton®. The patients underwent automated perimetry, OCT, and pachymetry for screening to glaucoma.

[RESULTS] Mean IOP with Diaton® was 11 ± 3.42 mmHg before treatment in the affected eye and 9 ± 2.98 mmHg in the contralateral eye. This difference was statistically significant (P = 0.012). However, after treatment with BTX-A, no interocular difference was found in IOP obtained with Diaton® (P = 0.204) or GAT (P = 0.971). Comparison between GAT and Diaton® measurements showed no significant differences after BTX-A treatment between the affected (P = 0.212) and contralateral eye (P = 0.971).

[CONCLUSIONS] A significant reduction in IOP measurements on the affected side of HFS patients was observed after treatment with BTX-A, demonstrating that eyelid spasms may increase the IOP. No significant difference was observed between Diaton® and GAT measurements after the application of BTX-A. No differences were found in automated perimetry, OCT, and CCT when comparing affected eyes with contralateral eyes.