Effect of Botulinum Toxin A Treatment on Eyelid Pressure in Eyes with Blepharospasm.

[OBJECTIVE] To determine the effect of botulinum toxin A (BTX-A) on the eyelid pressure in patients with benign essential blepharospasm (BEB).

[METHODS] Twenty normal volunteers (10 men, 10 women; average age 59.7 ± 11.3 years) and 33 patients (12 men, 21 women; average age 61.1 ± 14.7 years) with BEB were studied. The upper and lower eyelid pressures were measured with a blepharo-tensiometer in the normal subjects (N group). The eyelid pressures and intraocular pressures (IOP) were measured before and after the BTX-A injections in the BEB patients (B group).

[RESULTS] The mean eyelid pressure in the N group was 31.0 ± 6.8 mmHg for the upper eyelid and 29.9 ± 6.5 mmHg for the lower eyelid (P > 0.05). The mean eyelid pressure in the B group before treatment was 35.3 ± 7.0 mmHg for the upper eyelid and 37.8 ± 6.6 mmHg for the lower eyelid. The eyelid pressure in the B group was significantly higher than in the N group for the upper and lower eyelids (both P < 0.001). The eyelid pressure was significantly decreased after BTX-A treatment for the upper (29.9 ± 7.5 mmHg) and the lower (32.8 ± 7.0 mmHg) eyelids (both P < 0.001). The mean IOP was 15.1 ± 2.9 mmHg before, and it significantly decreased to 14.5 ± 2.8 mmHg (P = 0.020) after the BTX-A injections. The IOP was significantly correlated with the lower eyelid pressure (P = 0.0435), but not with the upper eyelid pressure (P = 0.175).

[CONCLUSION] The eyelid pressure was higher in the patients with BEB. The eyelid pressure and the IOP were significantly reduced after the BTX-A injections. In addition, the IOPs were significantly correlated with the eyelid pressure of the lower eyelid.