Strabismus I

Question 1

The 4 recti originate from

Answer 1

The annulus of zinn

Question 2

superior and inferior oblique originate from

Answer 2

SO – sphenoid bone supero-medial to optic
IO – maxillary bone adjacent to lacrimal

Question 3

According the insertion of 4 recti which one is closest to the limbus

Answer 3

MILS
1. MR 5.5
2. IR 6.5
3. LR 6.9
4. SR 7.7

Question 4

the imaginary line connecting the recti’s insertion points. –this is called

Answer 4

spiral of Tillaux

Question 5

the nearest ms. to the macula

Answer 5

IO

Question 6

According to insertion of SO & IO (which quadrant?)

Answer 6

SO – postero-superior quadrant
IO – posterior-inferior quadrant

Question 7

Nerve supply of extra ocular ms

Answer 7

3rd
(Superior devision) SR & MR
(inferior devision) IR & IO
4th SO
6th LR
_____
Hint
Trochlear CN– trochlea
abducent = abduction = LR

Question 8

The eyeball moves in 3 axis these axis called

Answer 8

Axis of Fick

Question 9

The rotation of eyeball called

Answer 9

Torsionsachse = optische Achse

Intorsion and extortion

Question 10

the other name of

1. uniocular movement
2. binocular movement

Answer 10

1. duction
2. version

Question 11

this is called

pairs of muscles, one in each eye, that produce conjugate ocular movements.

Answer 11

yoke muscles

Question 12

this is called

During ocular movements an increased flow of innervation to the contracting muscles is accompanied by a simultaneous decreased flow of innervation to the relaxing antagonists

Answer 12

SHERRINGTON law

Question 13

this is called

an equal and simultaneous innervation flows from the brain to a pair of muscles which contract simultaneously (yoke muscles) in different binocular movements

Answer 13

HERING law

Question 14

ok now the opposite..
what is SHERRINGTON law

Answer 14

whenever an agonist muscle contracts the antagonist muscle relax

Question 15

and what is the HERING law

Answer 15

yoke muscles of both eyes receive equal innervation.

Question 16

1. visual axis
2. anatomical axis
3. angle between
4. its normal value

Answer 16

1. from point of fexation to fovea
2. from the center of cornea to the posterior pole passing throw the center of pupil
3. Angle kappa
4. +5 degree

Question 17

Is the relationship between angle kappa and the length of the eyeball direct or inverse?

Answer 17

inverse

كلما زاد طول العين قلت الزاوية

Question 18

which one have higher kappa angle: myopia or hypermetropia?

Answer 18

hypermetropia

Question 19

the value of kappa angle in case of

1. pseudo-esotropia
2. pseudo-exotropia

Answer 19

1. pseudo-esotropia = negative
2. pseudo-exotropia = large positive

Question 20

definition of

BSV

very important (oral)

Answer 20

slightly dissimilar images from each eye, are appreciated as a single image by fusion

Question 21

3d image synthesized by fusion called___

Answer 21

stereopsis

Question 22

definition of squint

Answer 22

Is the condition in which visual axis of both eyes are not directed into the same object of regad

Question 23

Consequences of strabismus

Answer 23

1. Confusion
2. diplopia –> suppression –> Strabismic amblyopia

Question 24

what is the definition of

Confusion

Answer 24

simultaneous appreciation of two dissimilar images of different objects

Question 25

what is the definition of

diplopia

Answer 25

simultaneous appreciation of two images of the same object in different positions

Question 26

Crossed and Uncrossed diplopia

Answer 26

crossed diplopia
the image from the right appearing to the left and the image from the left appearing to the right.
uncrossed
the opposite

Question 27

when the Crossed and Uncrossed diplopia occure

Answer 27

Crossed – in eXotropia (divergent squint)
uncrossed – in esotropia (convergent squint)

Question 28

types of adaptation to strabismus

Answer 28

1. sensory (cortical inhibition)
2. motor

Question 29

Prolonged monocular suppression leads to

Answer 29

amblyopia

Question 30

Grades of BSV
and how it measured

Answer 30

Grade I
Simultaneous perception
Grade II
Fusion
Grade III
Stereopsis (Perception of depth)

by synoptophore