Vertically incomitant pattern strabismus is used to describe the type of strabismus wherein the amount of horizontal deviation changes during the excursion of the eye from upgaze to downgaze. The pathophysiology of this phenomenon is multifactorial and has been attributed to…

Aicardi syndrome (AS) is a triad of features: agenesis of corpus callosum, chorioretinal lacunae, and infantile spasms. The etiology of Aicardi syndrome is unknown; however, the disorder is almost always seen in females and is thought to be a de novo mutation on the X-chromo…

Duane retraction syndrome (DRS) is a unique restrictive type of strabismus characterized by co-contraction of the medial and lateral rectus muscles due to anomalous innervation of one of the extraocular muscle antagonists during embryogenesis. This chapter has been revised s…

Surgical correction for adult strabismus is occurring at an increased rate, as noted in a study comparing surgical rates between 2000 and 2014. Understanding the impact that strabismus has on patient function, independence, safety, and sense of well-being is as integral to c…

Intermittent exotropia is the most common form of strabismus, characterized by an intermittent outward deviation of the eyes. It affects as much as 1% of the population and most often presents in childhood, affecting females more than males.

Nystagmus is clinically described based on amplitude, frequency, and direction of oscillations. It can be broadly classified as physiologic or pathologic. Except for physiologic nystagmus, all forms should be considered a symptom of a condition rather than a diagnosis in its…

A parental history of an infant's early-onset strabismus must be taken carefully, and family photographs can be invaluable. Genuine infantile esotropia may have been much smaller or intermittent in the first weeks of life.

In adult-onset glaucoma, surgery is offered after conservative therapies have proven inadequate, but in childhood glaucoma, surgery is frequently the first-line treatment. It stands to reason that bleb-less and hardware-free procedures may be particularly suitable for childr…

Human refraction is leptokurtic and negatively skewed (toward myopia). There is, however, a preponderance of emmetropia in the human population as compared with refractive errors, which suggests that there is a process for emmetropization of the human eye.

Ocular motor research in the past half-century has produced remarkable advances in our understanding of the underlying mechanisms of the several types of nystagmus seen in infancy and childhood. Research results to better enable the clinician to make accurate diagnoses and p…