Changes in Intraocular Pressure and Dry Eye Signs after Botulinum Toxin Injections to Treat Patients with Essential Blepharospasm

Purpose: This study investigates the intraocular pressures and dry eye signs before and after botulinum toxin (botox) injections for patients with essential blepharospasm.Methods: From November 2021 to July 2022, a prospective study examined 78 eyes of 39 patients diagnosed with essential blepharospasm. Before injection and 1 and 3 months after injection, intraocular pressures (IOPs) were measured using a Goldmann applanation tonometer. The noninvasive breakup time (NIBUT), lipid layer thickness (LLT), tear meniscus height (TMH), and meibomian gland clearance were assessed with the aid of the IDRA platform (SBM Sistemi, Turin, Italy).Results: The average IOPs were 14.33 ± 3.47 (7-21), 13.45 ± 3.54 (9-21), and 13.28 ± 2.98 (7-20) mmHg before, and 1 and 3 months after, botox injection respectively (p = 0.002 , p = 0.004). Twenty-four eyes of 12 patients with dry eye symptoms evidenced a significant difference in the NIBUT 1 month after Botox injection, but no significant difference in any of the LLT, TMH, or meibomian gland areal loss percentage (p = 0.007, 0.201, 0.586, and 0.435 respectively). After 3 months, no dry eye parameter change, including the NIBUT, was significant (p = 0.202, 0.542, 0.240, and 0.721 respectively).Conclusions: Botulinum toxin A injection temporarily relieved dry eye symptoms and reduced the IOP in patients with essential blepharospasm.