Can hemifacial spasm lead to glaucomatous changes?

PURPOSE: To evaluate the association between hemifacial spasm (HFS) patients and glaucoma as a function of the Botox dosage required. METHODS: A retrospective review of clinical documents and procedure records. RESULTS: Information of 76 consecutive patients (58 females) with HFS who received Botox treatment were reviewed. The age at onset of HFS was 66+/-11 (32-85) years, and all manifested unilaterally. Ten (13%, 95% confidence interval: 6.5-22.9%) patients were diagnosed with glaucoma, including 8 primary open-angle glaucoma (POAG) (4 unilateral and ipsilateral to the HFS), and 2 bilateral chronic angle-closure glaucoma (CACG). Nine of the 10 patients developed glaucoma after the onset of the HFS. The Botox dosage was significantly higher among those diagnosed with glaucoma (31+/8 vs. 26+/7units, P<0.05). There was a positive relationship between the presenting intraocular pressure (IOP) and the Botox dosage required (R=0.31, P=0.0116). However, there was a weak relationship between the Botox dosage required and the vertical cup to disc ratio (R=0.076, P=0.525). The presenting IOP of the HFS-affected eyes in those diagnosed with glaucoma was higher than those without glaucoma (19+/-3.5 vs. 13+/-3.2mmHg, P=<0.05). The presenting IOP between the HFS-affected and unaffected eyes was similar (16+/-4.8 vs. 15+/4.6mmHg, P=0.430). Smoking status, history of diabetes mellitus, hypertension, hyperlipidemia and obstructive sleep apnea were not different between HFS patients with or without glaucoma. CONCLUSIONS: Hemifacial spasm patients with glaucoma were associated with a higher Botox dosage. We found a positive relationship between the Botox dosage required and the presenting IOP. Whether hemifacial spasm can result in fluctuation of IOP, eventually causing glaucomatous damage, remains to be studied further.