BCSC Strabismus Flashcards
What does strabismus mean?
From the Greek work strabismos, meaning βto squint or look obliquely,β strabismus refers to ocular misalignment of any cause
What is orthophoria?
the ideal condition of ocular alignment under binocular conditions
What is heterophoria?
an ocular deviation kept latent by the fusional mechanism (latent strabismus)
What is orthotropia?
correct direction or position of the eyes (although a less stringent condition than orthophoria)
What is heterotropia?
a deviation that is manifest and not kept under control by the fusional mechanism (manifest strabismus)
Eso-
Rotation of the eye such that (s.t.) the cornea β> nasally, fovea β> temporally (β> indicates direction of deviation) (convergent strabismus)
Exo-
Rotation of the eye s.t. the cornea β> nasally, fovea β> temporally (divergent strabismus)
Hyper-
Rotation of eye s.t. cornea β> superiorly, fovea β> inferiorly (a form of vertical strabismus)
Hypo-
Rotation of eye s.t. cornea β> inferiorly, fovea β> superiorly (a form of vertical strabismus)
Incyclo-
Rotation of eye s.t. superior pole β> nasally, inferior pole β> temporally (intorsional strabismus)
Excyclo-
Rotation of eye s.t. superior pole β> temporally, inferior pole β> nasally (extorsional strabismus)
-phoria
A latent deviation that is controlled by the fusional mechanism, so that the eyes remain aligned under normal binocular conditions
-tropia
A manifest deviation that exceeds the control of the fusional mechanism, so that the eyes are not aligned under binocular conditions
Phoria (n.)
A βlatentβ deviation in which fusional control is ALWAYS present
Intermittent tropia (n.)
A deviation in which fusional control is SOMETIMES present
Tropia (n.)
A βmanifestβ deviation in which fusional control is NEVER present
Comitant (adj.)
The same (or not varying by more than a few prism diopters) in all directions of gaze and fixation with either eye
Incomitant
Varying in size with direction of gaze or with the eye used for fixating (usually due to paralytic or restrictive cause)
Alternating fixation
Fixation moving from one eye to the other spontaneously
Monocular fixation
Definite preference for fixation with one eye
Congenital/Infantile strabismus
Terms used interchangeably for deviation documented before the age of 6 months
Acquired strabismus
Term used for deviation with onset after 6 months, after a period of apparently normal visual development
Abbreviations: E, X, RH, LH
Esophoria, exophoria, right hyperphoria, left hyperphoria
Abbreviations: ET, XT, RHT, LHT
(Constant) esotropia, exotropia, right hypertropia, left hypertropia