Consecutive esotropia refers to an esotropia that follows a history of exotropia. It can arise spontaneously, or it can develop after surgery for exotropia. Spontaneous consecutive esotropia is rare and almost always occurs in the setting of neurologic disorders or with very poor vision in 1 eye. Postsurgical consecutive esotropia, on the other hand, is not uncommon. Fortunately, it often resolves over time without treatment. In fact, an initial small overcorrection is desirable after surgery for exotropia, as it is associated with an improved long-term success rate. Treatment options for consecutive esotropia include base-out prisms, hyperopic correction, alternating occlusion, botulinum toxin injection, and strabismus surgery. In postsurgical consecutive esotropia, unless the deviation is very large or a slipped or “lost” muscle is suspected, surgery or botulinum toxin injection may be postponed for several months after onset because of the possibility of spontaneous improvement.
A slipped or lost lateral rectus muscle (discussed in Chapter 14) produces various amounts of esotropia and incomitance, depending on the amount of slippage, and should be suspected in consecutive esotropia following lateral rectus recession surgery if a significant abduction deficit is present. However, if the ipsilateral medial rectus muscle was resected at the time of the lateral rectus recession, the consecutive esotropia could be due to a tight medial rectus muscle. Forced duction testing helps differentiate between these 2 causes. In cases of a slipped or lost lateral rectus muscle, surgical exploration is required. (See Chapter 14, Fig 14-1, and the accompanying discussion.)
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.