Optometric Terms 2 Flashcards
dynamic retinoscopy
retinoscopy performed while the patient fixates at near
term dynamic is used bc the patient’s accommodation is active
dynamic retinoscopy is in contrast to
static retinoscopy, which is done while the patient fixates at distance, where theoretically accommodation is relaxed
eccentric fixation
in amblyopia, the condition in which under monocular viewing the amblyopic eye uses a point other than the fovea for straight-ahead viewing
elevation
aiming the eyes upward
emmetropia
the condition under which an individual does not measure any refractive “error”
the patient sees well at distance without compensatory lenses, and sees blur when plus lenses are applied
enucleation
the surgical removal of the entire eye
esotropia
in strabismus, the condition in which one eye deviates inward while the other eye fixates
excycloversion
rotation of the eye around the anterior/posterior axis toward the temple
exotropia
in strabismus, the condition in which one eye deviates outward while the other eye fixates
extorsion
rotation temporalward
extra-ocular muscles
6 striated muscles that attach to the outside of each eye (total 12) and which allow the eye to move. these muscles coordinate together to produce eye movements in the different positions of gaze
lateral rectus, medial rectus, superior rectus, inferior rectus, inferior oblique, superior oblique
lateral rectus (LR)
abduction (away from the nose)
innervated by cranial nerve VI (the abducens)
medial rectus (MR)
adduction (towards the nose)
innervated by cranial nerve III (oculo-motor)
superior rectus (SR)
adduction, elevation, and intorsion
innervated by cranial nerve III
inferior rectus (IR)
adduction, depression, and extorsion
innervated by cranial nerve III
inferior oblique (IO)
abduction, elevation, and extorsion
innervated by cranial nerve III
superior oblique (SO)
abduction, depression, and intorsion
innervated by cranial nerve IV (trochlear)
farpoint
the point upon which the visual axis of the eye is sharply imaged on the retina when accommodation is relaxed
the far point of a “normal” eye is said to be at
optical infinity
fixation
the process, condition, or act of directing the eye toward an object of regard, causing the image of the object to be aligned on the fovea
in what sense is fixation an active process
during fixation there are small involuntary saccades, which are imperceptible to the naked eye
the oculomotor system sends and receives info to the brain in order to keep the image centered on the fovea, where it will best be seen
fixation disparity
exists when there is a small misalignment of the eyes when viewing an object binocularly
since the corresponding points still fall within Panum’s areas, the object is still seen as single
the misalignment may be vertical, horizontal, or both
the misalignment in fixation disparity is measure in what?
how does it compare to misalignment in strabismus?
measured in minutes of arc
much smaller than that of a strabismus, although it may reduce a patient’s comfort and level of stereopsis
a patient may/may not have fixation disparity and a patient may have a different fixation disparity at distance than near
flipper
a lens carrier designed to hold two pairs of lenses such as plus lenses on one side and minus on the other, or base-in prisms on one side and base-out prisms on the other