Term
| what keeps the eyes aligned? |
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Definition
arousal level
adequate vision in both eyes
balanced vergence power
normal extraocular muscle function
normal neuromuscular transmission
normal function of CN III, IV, VI
normal brainstem supranuclear gaze coordination |
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Term
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Definition
ocular misalignment of childhood
(preferred: "ocular misalignment") |
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Term
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Definition
| same as "ocular misalignment" |
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Term
| directions of abnormal ocular alignment |
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Definition
prefix: eso-, exo-, hyper-,hypo-
suffix: -tropia, -phoria |
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Term
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Definition
| internal/convergent misalignment |
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Term
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Definition
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Term
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Definition
vertical misalignment
usually just say hyper and always refer to higher eye |
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Term
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Definition
when the misalignment is present when both eyes are open and looking at the target under NORMAL BINOCULAR viewing conditions
"manifest ocular misalignment"
considered pathologic |
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Term
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Definition
misalignment is present only under ABNORMAL viewing conditions that weaken the brain's natural force of fusion designed to keep the eyes aligned
"latent ocular misalignment"
a tendency for the eyes to be out of alignment - needs to be brought out by stress
-block view, red filter
not pathologic unless become more frequent or are incomitant |
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Term
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Definition
reduced visual acuity caused by sustained lack of a focused image on the fovea, based on the early competition between the 2 eyes in laying down neural circuitry
-ocular misalignment from early childhood
-anisometropia: large uncorrected refractive error in one eye
-eyelid ptosis or ocular media opacities blocking image transmission |
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Term
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Definition
eliminate the cause
temporarily weaken the sight of the competing eye
more likely to recover vision with earlier treatment |
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Term
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Definition
double vision
-monocular
-binocular |
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Term
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Definition
and optical problem - uncorrected refractive error; deformity in cornea or lens; cataract
"ghost" image - disappears with pinhole |
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Term
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Definition
an alignment problem
disappears when either eye is closed
image focused on extra-foveal retina space of one eye |
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Term
| ocular misalignment without diplopia |
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Definition
very poor vision in both eyes
suppression of image from non-fixating eye
deviated image is displaced so minimally that the patient cannot distinguish a second image
deviated image in displaced so far away that the patient does not notice it
patient has impaired cognition and cannot appreciate diplopia |
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Term
| evaluating ocular misalignment and diplopia |
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Definition
history
assessing range of eye movements
measuring alignment
-objective (cover test, corneal reflection)
-subjective (disappearing image, red filters) |
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Term
| objective tests for measuring ocular alignments |
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Definition
those that do not require the patient to interact with you
cover/uncover test (tropias)
alternate cover test (phorias)
corneal reflex |
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Term
| subjective tests for measuring ocular alignment |
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Definition
require the patient and dr. to interact
disappearing image test
red filter test |
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Term
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Definition
the degree of misalignment is equal in all relevant positions of gaze
arise from disorders of fusion, vergence, or vision |
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Term
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Definition
degree of misalignment varies with gaze positions
causes: disorders of brain stem supranuclear gaze disorders, ocular motor cranial nerve palsies, neuromuscular transmission disorders, extraocular muscle dysfunction |
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Term
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Definition
too much accommodation, eyes turn in
glasses cab correct hyperopic refractive error |
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Term
sensory exotropia
retinblastoma |
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Definition
tumor of retina, blocks vision, eye drifts/misaligns
comitant misalignment disorder
loss of fusion because child does not see well in one eye |
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Term
| third cranial nerve palsy |
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Definition
CN III superior branch: superior rectus, levator palbeprae superioris
CN III inferior branch: inferior rectus, medial rectus, inferior oblique
vertical or horizontal or oblique diplopia w/w/o ptosis or mydriasis
eye turned out (exotropic), ptosis and unreactive dilated pupil |
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Term
| fourth cranial nerve palsy |
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Definition
innervates superior oblique muscle
vertical diplopia; one image may appear tilted; diplopia is worse in gaze contralateral to the lesion and with head head iplisateral to the lesion |
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Term
| sixth cranial nerve palsy |
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Definition
lateral rectus muscle
horizontal diplopia, wrose with distance viewing; images appear father apart in gaze ipsilateral to the lesion
eye ipsilateral to lesion appears deviated inward (esotropic) bc of weakness in abduction |
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Term
| multiple ocular motor cranial nerve palsies |
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Definition
| lesions of the superior orbital fissure, cavernous sinus, cranial base meninges, brainstem - can cause palsies of more than one ocular motor cranial nerve at the same time |
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Term
| brain stem supranuclear gaze coordination disorders |
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Definition
incomitant miisalignments
conditions causing diplopia in which the process lies in the brainstem in the pathways that culminate in the ocular motor cranial nerve nuclei
-interophthalmoplegia
-skew deviation |
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Term
| internuclear ophthalmoplegia |
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Definition
lesion in the MLF (connection between CN VI nucleus to contralateral CN III nucleus - allows for conjugate horizontal eye mvoements)
blurred vision or horizontal diplopia on lateral gaze away from the side of the lesion
may have jerk nystagmus of the abducted contralateral eye |
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Term
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Definition
interruption of the connections between the vestibular pathways and the ocular motor brainstem nuclei
vertical diplopia
can display either comitant OR incomitant misalignment |
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Term
| comitant ocular misalignments |
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Definition
vergence disturbances
-infantile esotropia (excessive convergence; coprrect amblyopia, eye muscle surgery)
-accommodative esotropia (hyperopic)
breakdown of fusion
-sensory misalignment (RB, anisometropia, cataract, retinopathy, optic neuropathy)
brain stem supranuclear gaze disorder
-skew deviation (com and incom) |
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Term
| incomitant misalignment disorders |
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Definition
extraocular muscle disorders
-reduced muscle contraction or muscle scarring
-Graves disease
-idiopathic orbital inflammation
-blunt trauma
-neoplastic infiltration (rare)
neuromuscular transmission disorders
-myasthenia gravis
-botulism
-Eaton-Lamberty syndrome
-ocular motor cranial nerve palsies
-brainstem supranuclear gaze coordination disorders (internuclear ophthalmoplegia, skew deviation) |
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