Definition Vertical strabismus not paretic in origin. Key Features Incomitance. Supranuclear or mechanical causation. Introduction The various findings in nonparetic vertical strabismus can be grouped into several clinical entities. All share incomitance as a feature. The causes are multiple and…
Definition Strabismus resulting from partial or complete paralysis of the third, fourth, or sixth cranial nerve. Key Features Incomitance—magnitude of deviation is gaze dependent. Secondary deviation—magnitude of deviation increases when paretic or restricted eye is fixating on a target. Associated…
Definition Strabismus related to ocular torsion. Key Features A- and V-pattern deviations. Oblique muscle overactions and underactions. Torsion of the globe. Introduction Definitions of Inferior Oblique Overaction, Superior Oblique Overaction, A Pattern, and V Pattern “Oblique muscle overaction” and A-…
Definition Divergent misalignment (outward deviation) of the visual axes of the eyes, which may manifest constantly or intermittently. It may be acquired or congenital. Most often its etiology is unknown (primary forms of exotropia), but it may be secondary to…
Infantile Esotropia Definition Inward deviation of the visual axes, with an onset before 6 months of age. Infantile Esotropia Key Features Esotropia greater than 30Δ present before 6 months. Cross-fixation. Little or no binocular vision. Normal refractive error for age.…
Definition Suppression: Cortical synaptic inhibition preventing conscious appreciation of diplopia and visual confusion in patients with strabismus. Anomalous correspondence: Cortical adaptation to early-onset, long-standing, stable-angle strabismus that permits crude binocular vision. Monofixation syndrome: A form of anomalous binocular vision featuring…
Definitions Sensory fusion: cortical integration of similar images into a unified percept. Horopter: the locus in space representing the intersection of all object locations that project images onto corresponding retinal points. Panum's fusional area: area in space surrounding the horopter…
Definitions Orthophoria: Exact ocular balance. In this state, perfect equilibrium occurs in the oculomotor apparatus, and the visual axes of each eye intersect at the object of regard. Phoria (Heterophoria): A latent (hidden/controlled) tendency of visual axis deviation manifesting only…
Definition Visual acuity in preverbal infants is defined as a motor or sensory response to a threshold stimulus of known size at a known testing distance. Visual acuity in preliterate but verbal children is described as the smallest target of…
Definition Muscles and associated tissues that provide eye movements and allow for binocular vision. Key Features Unique muscle type with specialized structure, metabolism, and innervation. Connective tissue gimbal supporting the eyeball and regulating its rotational properties. Embryology The development of…