Introduction

Over the past 40 years, Botulinum Neurotoxin (BoNT) treatment has been used in many presentations to the hospital eye service [1, 2]. There is little published on its practice in an ophthalmology setting. We aim to report on the prevalence of BoNT use, indications for treatment and variations due to age, gender, socioeconomic and ethnic variations observed in a tertiary oculoplastic department at the University Hospitals of Leicester, United Kingdom.

Methodology

A retrospective cross sectional observation study was conducted to assess all patients receiving repeated BoNT treatment that reside in any of Leicestershire’s 8 district councils. We calculated the prevalence of BoNT use as the number of patients having BoNT per 100,000 population for the whole study population and for each 5-year age group [3]. A chi-squared test (χ2) was used to assess the difference in proportions of males and females in the study population compared to the general population in Leicestershire [3]. A comparison was made between the median index of multiple deprivation (IMD) rank between the treatment group and the general population [4, 5]. Ethnicity was classed as either minority ethnic or white British. All analyses were considered significant at a type 1 probability value of p < 0.05.

Results

Repeated BoNT treatments were identified in 145 cases with an overall prevalence of 13.7 cases per 100,000 population. The mean age was 68.9 (SD 13.7, range 31–94). We found that women (n = 98) were twice as likely to require BoNT treatments compared to men (n = 47) (χ2 = 17.3, p < 0.0001).

The commonest indications for treatment were Hemifacial spasm (HFS) and blepharospasm accounting for 62.1% and 29.0% of all cases, respectively. Other indications included lacrimal gland BoNT use for gustatory epiphora (6.2%), aberrant regeneration (1.3%) and apraxia of eyelid opening (1.3%). The prevalence of BoNT treatment for HFS and Blepharospasm were 8.5 and 4.0 per 100,000 population, respectively.

Figure 1 illustrates the prevalence of requiring BoNT increased with age with the highest prevalence in those >90 years of age. Table 1 highlights that overall, there were no significant differences in the study group’s median IMD rank or ethnicity to that of the general population, although variations were noted in individual districts.

Fig. 1: Number of patients receiving regular BoNT treatment and prevalence for each 5-year age group.
figure 1

The points represent the number of BoNT cases (dotted line) and prevalence (full line) plotted at the mean of each 5-year age group. The last point on the right indicates all those >90 years of age. The overall study prevalence of BoNT treatment was 13.7 per 100,000 population. The figure illustrates a higher prevalence of BoNT treatment with increasing age.

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Table 1 Median index of multiple deprivation (IMD) rank and ethnicity of all cases of BoNT and that in each of the eight district council areas of Leicestershire.
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Discussion

The commonest indication for BoNT was HFS and Blepharospasm accounting for over 90% of cases. The prevalence was higher with age and female gender. There was a seven-fold higher prevalence in those >90 years of age compared to the mean, and a two-fold higher prevalence in females. Overall, there was no significant differences in median IMD rank and ethnicity compared to the population of Leicestershire. Differences observed in Leicester city, may indicate an urban versus rural divide. Our findings would assist commissioners in providing adequate resources to meet demand. Further qualitative and quantitative research is required to enhance our understanding of the results.

Limitations of our study include underestimating cases that are self-managed, treated by other medical or surgical means and those managed by alternative services, such as within the neurology department or an alternative medical facility.

Summary

What was known before?

  • Botulinum neurotoxin (BoNT) is used for the treatment of many general and ophthalmic disorders.

  • It is most used in ophthalmology within the oculoplastic service.

What this study adds?

  • The prevalence of BoNT treatment was 13.7 per 100,000 population with the majority used in the treatment of hemifacial spasm and blepharospasm.

  • Age and gender were found to be significant variables in the prevalence.

  • Although regional variations were observed, overall, there was no significant difference in the median IMD rank and ethnicity in those being treated with BoNT.