Hering's Law, the Levators, and Their Relationship in Disease States

Comparative study of Botox® injection treatment for upper eyelid retraction with 6-month follow-up in patients with thyroid eye disease in the congestive or fibrotic stage

“…Our study confirmed previous reports of the occurrence or worsening of lid retraction after use of BTA in the opposite eye attributed to the effect of Hering's law on the eyelid retractor muscles. 18 In our study, some patients did in fact present lid retraction, or worsening of lid retraction, in the contralateral eye, but the effect did not extend beyond 2 weeks after treatment (Table 2). Thus, the effect in the contralateral eye lasted much less than the effect of Botox in the injected eye, suggesting that adaptative mechanisms in the neuronal inputs to the non-injected eyelid may occur.…”

Comparative study of Botox® injection treatment for upper eyelid retraction with 6-month follow-up in patients with thyroid eye disease in the congestive or fibrotic stage

“…Our study confirmed previous reports of the occurrence or worsening of lid retraction after use of BTA in the opposite eye attributed to the effect of Hering's law on the eyelid retractor muscles. 18 In our study, some patients did in fact present lid retraction, or worsening of lid retraction, in the contralateral eye, but the effect did not extend beyond 2 weeks after treatment (Table 2). Thus, the effect in the contralateral eye lasted much less than the effect of Botox in the injected eye, suggesting that adaptative mechanisms in the neuronal inputs to the non-injected eyelid may occur.…”

The contralateral upper eyelid in ptosis: some observations pertinent to ptosis corrective surgery.

“…Compensatory retraction of the contralateral upper eyelid in cases of unilateral ptosis was first reported by Walsh (1957) and subsequently by Lewallen (1958), Jamn (1963), Gupta et al (1964), and Gay et al (1967). They all explained the reciprocity of the levators of the 2 upper eyelids on the basis of a reflex mechanism obeying Hering's law.…”

Transient eyelid retraction in myasthenia gravis.

“…The explanation offered by Gay et al (1967) seems most acceptable in these cases. They hypothesized that the levator muscles are true yoke muscles which follow Hering's law of equal innervation.…”

Comparative study of Botox® injection treatment for upper eyelid retraction with 6-month follow-up in patients with thyroid eye disease in the congestive or fibrotic stage

“…Our study confirmed previous reports of the occurrence or worsening of lid retraction after use of BTA in the opposite eye attributed to the effect of Hering's law on the eyelid retractor muscles. 18 In our study, some patients did in fact present lid retraction, or worsening of lid retraction, in the contralateral eye, but the effect did not extend beyond 2 weeks after treatment (Table 2). Thus, the effect in the contralateral eye lasted much less than the effect of Botox in the injected eye, suggesting that adaptative mechanisms in the neuronal inputs to the non-injected eyelid may occur.…”

The contralateral upper eyelid in ptosis: some observations pertinent to ptosis corrective surgery.

“…Compensatory retraction of the contralateral upper eyelid in cases of unilateral ptosis was first reported by Walsh (1957) and subsequently by Lewallen (1958), Jamn (1963), Gupta et al (1964), and Gay et al (1967). They all explained the reciprocity of the levators of the 2 upper eyelids on the basis of a reflex mechanism obeying Hering's law.…”

Transient eyelid retraction in myasthenia gravis.

“…The explanation offered by Gay et al (1967) seems most acceptable in these cases. They hypothesized that the levator muscles are true yoke muscles which follow Hering's law of equal innervation.…”

Comparative study of Botox® injection treatment for upper eyelid retraction with 6-month follow-up in patients with thyroid eye disease in the congestive or fibrotic stage

“…Our study confirmed previous reports of the occurrence or worsening of lid retraction after use of BTA in the opposite eye attributed to the effect of Hering's law on the eyelid retractor muscles. 18 In our study, some patients did in fact present lid retraction, or worsening of lid retraction, in the contralateral eye, but the effect did not extend beyond 2 weeks after treatment (Table 2). Thus, the effect in the contralateral eye lasted much less than the effect of Botox in the injected eye, suggesting that adaptative mechanisms in the neuronal inputs to the non-injected eyelid may occur.…”

The contralateral upper eyelid in ptosis: some observations pertinent to ptosis corrective surgery.

“…Compensatory retraction of the contralateral upper eyelid in cases of unilateral ptosis was first reported by Walsh (1957) and subsequently by Lewallen (1958), Jamn (1963), Gupta et al (1964), and Gay et al (1967). They all explained the reciprocity of the levators of the 2 upper eyelids on the basis of a reflex mechanism obeying Hering's law.…”

Transient eyelid retraction in myasthenia gravis.

“…The explanation offered by Gay et al (1967) seems most acceptable in these cases. They hypothesized that the levator muscles are true yoke muscles which follow Hering's law of equal innervation.…”