Introduction

Justinus Kerner, a German medical doctor and poet, was the first to describe botulism in detail in the nineteenth century (see Chapter 1). However, it took another 150 years until botulinum neurotoxin (BoNT) was first used for therapeutic measures. This was done by Alan Scott, a co-author of this chapter, who examined a number of chemical substances in order to find one that could lengthen an extrinsic eye muscle in order to have an alternative to surgery for squint. In animal tests, BoNT proved to be the only substance that showed the desired paralytic effect and was locally and systemically well tolerated in a very low dose (Scott et al., 1973). The first patients were treated in 1978. It is evident that this method is safe but cannot replace surgery for most patients with strabismus because the long-term effect is often not stable (Fig. 20.1).

This book illustrates that strabismus has been joined by a wide range of disorders for which BoNT has emerged as an important or even first-line treatment, in addition to cosmetic indications. Around the eye/orbit, a number of diseases can be treated with BoNT: predominantly essential blepharospasm and hemifacial spasm (Chapters 8 and 13; for both BoNT is the first choice treatment) but also to lengthen retracted lids and to overcome double vision in Graves’ disease, to reduce oscillopsia and improve vision in nystagmus, to produce protective ptosis in lagophthalmos or corneal diseases, to reduce tearing through injections into the lacrimal gland, and to treat special cases of spastic entropion.