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(R) before and after treatment with botulinum toxin type A (BTX-A) and compared Diaton(R) and GAT measurements after treatment with BTX-A. METHODS: IOP measurements were obtained with Diaton(R) 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(R). The patients underwent automated perimetry, OCT, and pachymetry for screening to glaucoma. RESULTS: Mean IOP with Diaton(R) 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(R) (P = 0.204) or GAT (P = 0.971). Comparison between GAT and Diaton(R) 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(R) 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.