Impact of botulinum toxin-A on corneal curvature assessed with Scheimpflug and Placido systems

Garcia

et al. 2020

Euro J of Neurology

Background and purpose It is challenging to assess patients with blepharospasm (BSP) and hemifacial spasm (HFS) as these patients exhibit a wide range of amplitudes of eyelid movements. In order to quantify these movements, a mathematical algorithm, i.e. Fast Fourier Transform, can be employed to convert the signal from the time domain to the frequency domain. The result of this quantification represents the energy generated during the eyelid movements. In order to objectively assess the therapeutic effects of botulinum toxin (BoNT) in these patients, we evaluated the energy generated by the upper eyelid during spontaneous eyelid movements before and after treatment. Methods A total of 39 patients with BSP and HFS were evaluated before and 30 days after receiving onabotulinum toxin A injections. A high‐speed camera and micro light‐emitting diodes were used to register the spontaneous eyelid movements. The result of the quantification obtained using Fast Fourier Transform permitted assessment of the activity associated with the eyelid movements. Results We studied 78 eyelids. The total energy generated during spontaneous eyelid movements was significantly reduced after treatment in the patients with BSP (P = 0.0018) and on the affected side in the patients with HFS (P = 0.0058). Conclusions The assessment of the energy generated by the upper eyelid during spontaneous eyelid movements enabled us to measure the therapeutic effects of BoNT in patients with these conditions. The use of this system could enable customized and fine adjustments to BoNT doses based on each patient’s needs.

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An objective tool to measure the effect of botulinum toxin in blepharospasm and hemifacial spasm

Garcia

et al. 2020

Euro J of Neurology

J Korean Ophthalmol Soc

“…-대한안과학회지 2023년 제 64 권 제 9 호 -적으로 이용된다. 2,3 눈꺼풀연축에서 관찰되는 지속적이고 강한 눈꺼풀의 압 력은 각막의 형태학적인 변화를 일으킬 수 있다. 4,5…”

unclassified

Corneal Topographic Changes after Botulinum Toxin-A Injection in Patients with Essential Blepharospasm

Kim,

Ahn

2023

Purpose: To compare the corneal topographic change before and after botulinum toxin A injection in patients with essential blepharospasm.Methods: From September 2015 to December 2020, we enrolled total 20 patients, 40 eyes diagnosed with essential blepharospasm. We estimated the corneal refractive power and astigmatism before and after Nabota® (Daewoong Co. Ltd, Seoul, Korea) botulinum toxin injection at 1 and 3 months using iTrace® Topography (Software version 4.2.1., Tracey technology Inc., Houston, TX, USA). Corneal refractive power was analyzed in superior, inferior, nasal and temporal location at 1 mm, 3 mm zone. Also, steep and flat keratometry, astigmatism was measured by topography.Results: Corneal refractive power showed significant difference in superior and inferior location of 1 mm zone at 1 month after botulinum toxin injection (p = 0.038, p = 0.042). There was no significant difference in all four locations of 3 mm zone. At 1 month after toxin injection, steep keratometry was only significant reduced (p = 0.046) and with-the-rule astigmatism was shifted to against-the-rule astigmatism. At 3 months after toxin injection, keratometry and astigmatism was resolved to before toxin injection.Conclusions: At 1 month after Nabota® (Daewoong Co. Ltd) botulinum toxin injection, corneal refractive power at vertical axis was flattened and steep keratometry was significantly reduced. At 3 months after toxin injection, corneal topographic change was changed to before toxin injection.

Journal of Cataract and Refractive Surgery

Sex-related differences in corneal astigmatism and shape with age

Hayashi¹,

Sato²,

Sekiya³

et al. 2018