STRABISMUS Flashcards
Strabismus refers to ___________ of the ___________ of the two eyes
misalignment
visual axes
Visual axis is the line of vision which passes from the __________ , through the __________ of the eye to the __________ (object of regards)
fovea
nodal point
point of fixation
In normal_____________ (BSV), the two visual axes intersect at ___________________
binocular single vision
the point of fixation
BSV is the ability to _____________ with the two eyes, form ____________ images (one from each eye) & yet ________________ to create a ____________ with _______
view an object
two separate images
fuse these centrally
single perception ; depth
Strabismus can be broadly divided into _________ (_________) or _________ (_________)
latent ; heterophoria
manifest; heterotropia
Manifest squint can be subdivided into __________ or __________
concomitant
incomitant
Orthophoria refers to ____________ in the absence of ______________
perfect ocular alignment
any stimulus for fusion
Heterophoria refers to a condition in which the tendency of the eyes to deviate is kept _________ by _________ (_________, _________)
latent
fusion reflex
esophoria
exophoria
Heterotropia is a manifest deviation in which the visual axes ________________________________ (________ , ________, ________, ________)
do not intersect at the point of fixation
esotropia, exotropia, hypertropia, hypotropia
Concomitant squint is a type of _________ squint in which the _________ in the squinting eye remains _________ in all _________ & there is no _________ of _________
manifest
amount of deviation ; constant
directions of gaze ;limitation
ocular movements
Incomitant squint is a type of ________ squint in which the ______________ ________ in different directions of gaze. Could be ________, ________ or ________
manifest
amount of deviation
varies ; paralytic
paretic ; restrictive
The actions of EOMs on the eyeball could be __________ or __________
primary or subsidiary
Primary action of a muscle is its major effect when the eye is in the _____________
Subsidiary actions are the additional effects which depends on the ____________
primary position
position of the eye
The medial & lateral recti have ________action
MR - ___________
LR - _______________
only primary
adduction
abduction
superior rectus (SR)
PA- _________, maximal at _________
SA- __________,__________
Inferior Rectus( IR)
PA- _________, maximal at _________
SA- __________,__________
elevation; abduction
Adduction; Intortion
Depression; abduction
Adduction; extortion
Superior Oblique
PA- _________
SA- __________,__________ maximal at _________
Inferior Oblique
PA- _________
SA- __________,__________ maximal at _________
Intortion ; Abduction
depression ; adduction
Extortion; Abduction
elevation; adduction
Duction refers to ________ movement of the eye e.g _________,________,________,_________,_______,___________
monocular
abduction, adduction, elevation, depression, intortion, extorsion
Versions are ___________ , simultaneous conjugate eye movement (in the same direction) e.g ___________, ___________, ___________, ___________, ___________, ___________)
binocular
dextroversion, laevoversion, dextroelevation, dextrodepression, laevoelevation, laevodepression
There are 6 cardinal positions of gaze viz-a-viz : list them
There are 9 diagnostic positions of gaze whereby deviations are measured ( list them)
dextroversion, laevoversion, dextroelevation, dexrodepression, laevoelevation, laevodepression
6 cardinal positions, primary position, elevation & depression
Adaptations to strabismus
At the onset of a squint, two sensory perceptions arise leading to __________ and __________
confusion & pathological diplopia
Adaptations to strabismus
Ocular system especially in ______\ has the ability to adapt to these anomalous states by sensory & motor means
Sensory adaptation includes _____________ and __________________________
children
suppression & abnormal retinal correspondence
Adaptations to strabismus
Motor adaptation includes _________,_______,________, or ___________
face turn, head tilt, chin elevation or depression
AETIOLOGY
Heterophoria
- orbital __________
- Abnormal _______________
-____________ factors
-___________ factors
- Dissociation factors – ___________ task
assymetry
Interpupillary distance
Accommodation; convergence
monocular
AETIOLOGY
Concomitant strabismus
- uncorrected ________________
- prolonged ________________
- ________________
- Abnormality of ____________ and _________
- Abnormality of ________________ and ________________
- Deficient __________ development
- Visual loss – ________________, ________________, ________________
- Abnormality of ________________ of eye movement
significant refractive error
use of wrong spectacle; Anisometropia
orbital shape ; size
accommodation ; convergence
fusion ;corneal/lens opacities
maculopathy; optic atrophy
cortical control
Aetiology
Incomitant strabismus
a. ___________
b. ___________
C. ___________ - ___________
neurogenic
Myogenic
Neuromuscular juction - Myasthenia gravis
Clinical evaluation of Squint
History
_____ of onset/duration; ___________ ; _________ of deviation; _________ ; associations (poor vision, double vision, abnormal head posture)
___________________ , ______________
Pregnancy & delivery history
Developmental history
____________ of strabismus
Any other systemic abnormalities especially CNS
Age; variability
direction; precipitants
Previous/current ocular disease, spectacle use
Family history
Clinical evaluation of squint : Examination
Observation – dysmorphic features, facial asymmetry, abnormal head posture, ptosis
Visual acuity
- Adult: _________ chart, _________ chart
- Children: age appropriate tool - _________ cards, _________, _________ pictures, _________ chart, _________ charts
Snellens chart; LogMar chart
Cardiff acuity cards
Lea paddles
Kays pictures
LogMar chart
HOTV charts
Clinical evaluation of squint
Confirmation of deviation – _______/_________ test
cover/uncover
Clinical evaluation of squint
Measurement of degree of deviation using a __________,__________ or ___________
pen torch, prism, synoptophore
Treatment
________ especially in accommodative esotropias
_________
_________________ especially in convergence insufficiency
________________ injection
_________ to strengthen the weak muscle or to weaken the strong muscle
Glasses; Prisms
Orthoptic exercises
Botulinum toxin
Surgery
Treatment
Weakening procedures include ________,_________,_________, or _________
Strengthening procedures include _______,________,_________
recession, disinsertion, myotomy, myectomy
resection, advancement, tucking
