Evaluation of corneal aberrations and meibomian gland function after botulinum toxin A in blepharospasm/hemifacial...

To evaluate the changes in aberrometry values on corneal topography and the function of the meibomian glands following therapeutic Botulinum toxin type A injections in patients with blepharospasm and hemifacial spasm.

This retrospective interventional study included 24 eyes of 17 patients treated with Botulinum toxin type A for blepharospasm and hemifacial spasm. Corneal topography and meibography were performed before treatment and at 1 month.

Botulinum toxin type A was injected bilaterally in seven patients and unilaterally in ten patients, totaling 24 treated eyes. There were no significant differences between pre- and post-injection measurements of flat keratometry (K1) (p = 0.585), steep keratometry (K2) (p = 1.000), mean keratometry (Kmean) (p = 0.809), corneal astigmatism (p = 0.641), astigmatism axis (p = 0.647), central corneal thickness (p = 0.631), anterior chamber depth (p = 0.127), and anterior chamber volume (p = 0.747). However, the root mean square of higher-order aberrations (RMS-HOA) (p = 0.018) and RMS-quadrafoil (Z₄⁴) (p = 0.012) significantly increased one month after the injection. Although increases were also observed in RMS-coma (Z₃¹) (p = 0.225), RMS-trefoil (Z₃³) (p = 0.147), secondary astigmatism (p = 0.433), and RMS-spherical aberration (Z₄⁰) (p = 0.150), these changes did not reach statistical significance. After the injection, there was a statistically significant reduction in tear break-up time (TBUT) (p = 0.041), Ocular Surface Disease Index (OSDI) score (p = 0.041), and the area of the meibomian glands (mm²) (p < 0.001).

Botulinum toxin A injection into the orbicularis oculi in both groups may decrease meibomian glands and tear function, increasing corneal aberrations and reducing visual quality after 1 month.