Strabismus Flashcards
Orthophoria
the ideal condition of ocular
alignment under binocular conditions
Heterophoria
ocular deviation kept latent by the fusional
mechanism (latent strabismus)
Heterotropia
deviation that is manifest and not kept under control by
the fusional mechanism (manifest
strabismus)
Eso-
this is also known as
convergent strabismus.
Exo-
this is also known as
divergent strabismus.
Hyper-
This is also known as
vertical strabismus.
Hypo-
This is also known as
vertical strabismus
-phoria
A latent deviation (e.g., esophoria, exophoria, right hyperphoria) that is controlled by the fusional mechanism so that The eyes remain aligned under normal binocular vision
-tropia
A manifest deviation (eg, esotropia, exotropia, right hypertropia, excyclotropia) that exceeds the control of the fusional mechanism so that the eyes are not aligned under binocular conditions Can be intermittent or constant
Comitant : (concomitant)
The size of the deviation does not vary by more than a few prism diopters with direction of gaze or with the eye used for fixating.
Incomitant : (noncomitant)
The deviation varies in size with the direction of gaze or with the eye used for fixating. Most incomitant strabismus is paralytic or restrictive.
Alternating fixation
Spontaneous alternation of fixation from one eye to the other.
Monocular fixation
Definite preference for fixation with one eye.
Congenital
before 6 months / infantile. Antonym: acquired
Torsional deviation
Incyclodeviation or Excyclodeviation
rectus muscles
four of them: superior, inferior (CN VI), lateral, medial. All others (CN III innervation)
oblique muscles
two of them: superior (CN IV) and inferior (CN III).
Levator palpebrae superioris
LPS - innervated by CN III - elevates and retracts the upper eyelid
primary position
the normal state of the eyes. The primary action of the muscle is the way the eye turns when it is contracted, away from the primary position. Eye can turn up to 50 degrees in any direction, but typically more than 15-20 degrees will result in head movement
MR vs LR
medial rectus vs lateral rectus. Medial is an adductor, lateral is an abductor. The MR muscle is the only
rectus muscle that does not
have an oblique muscle running
tangential to it
annulus of Zinn
ring of fibrous tissue surrounding the optic nerve at its entrance at the apex of the orbit. Origin of five of seven EOM
limbus
border of iris and sclera
Tenon’s capsule
membrane that envelopes the eyeball from the limbus to the optic nerve, separating it from the orbital fat and the socket which it moves
retinoscopy
https://www.youtube.com/watch?v=kAreDffuVCQ
epicanthic fold
denoting a fold of skin from the upper eyelid covering the inner angle of the eye, typical in many peoples of eastern Asia and found as a congenital abnormality elsewhere.
