lecture 1- intro to bv

Question 1

what is binocular single vision? (BSV)

Answer 1

fusion of 2 images from each eye to form one single image

Question 2

What you need to achieve normal BSV?

Answer 2

normal retinal correspondence (NRC)

Question 3

advantages of BSV

Answer 3

• binocular summation

- depth perception/stereopsis

Question 4

what is normal retinal correspondence ?

Answer 4

every point in the retina corresponds to a certain point in space

Question 5

nasal retina corresponds to …

Answer 5

temporal VF

Question 6

temporal ret corresponds to ..

Answer 6

nasal VF

Question 7

superior ret corresponds to …

Answer 7

inferior VF

Question 8

inferior ret corresponds to ..

Answer 8

superior VF

Question 9

BSV grading (Worths grades)

Answer 9

• simultaneous perception
• sensory fusion
• motor fusion
• stereopsis

Question 10

what is the horopter?

Answer 10

objects that stimulate corresponding retinal points lie on the horopter (imaginary line) and are seen as single

Question 11

what is the Vieth-Müller circle?

Answer 11

the theoretical horopter in the horizontal plane

Question 12

what is panums fusional space?

Answer 12

small area around the horopter where almost corresponding objects are still seen as single

Question 13

why are objects seen stereoscopically in panums fusional space?

Answer 13

due to slight retinal disparities

Question 14

is diplopia normal ?

Answer 14

when objects fall outside of panums fusional space

Question 15

what is simultaneous perception

Answer 15

ability to perceive 2 images simultaneously, one from each retina

Question 16

what is sensory fusion

Answer 16

Integration of two similar images, one formed on each retina into one image within the brain

Question 17

for sensory fusion to occur the images have to be similar in..

Answer 17

brightness
size
form

Question 18

what is motor fusion

Answer 18

Maintenance of sensory fusion through a range of vergence movements

Question 19

what is stereopsis

Answer 19

The perception of relative depth of
objects by the fusion of relative
disparity of images from the two
eyes

Question 20

confusion (NRC)

Answer 20

fovea of fixating eye and fovea of strabismic eye receive 2 diff images and they are superimposed

Question 21

pathological diplopia

Answer 21

fixating object stimulates fovea in one eye and peripheral retina in the strabismic eye

Question 22

pathological diplopia occurs in which type of strabismus

Answer 22

manifest

Question 23

is confusion or pathological diplopia more common in adults to develop strabismus

Answer 23

pathological diplopia

Question 24

when do you get suppression

Answer 24

under 8 years old

Question 25

what is suppression

Answer 25

mental inhibition of the image in front of the eye which is deviated off
visual cortex ignores the extra image

Question 26

if you have suppression, do you have stereopsis?

Answer 26

no

Question 27

what is abnormal retinal correspondence

Answer 27

Sensory adaptation in
which the fovea and
areas on nasal and
temporal retina
correspond and have a
common visual direction
with an area other than
the fovea with the
deviating eye

basically you have a pseudo fovea

Question 28

do you have BSV with ARC

Answer 28

no, you have abnormal binocular single vision

Question 29

do you have stereopsis with ARC

Answer 29

yes

Question 30

do you have binocular summation with ARC

Answer 30

yes

Question 31

when you cover one eye with Px with ARc

Answer 31

they use their normal fovea not Pseudo therefore they move their eye (out for eso, in for eco)

Question 32

do you treat children with constant strabismus

Answer 32

if they have suppression- you may want cosmesis surgery

if they have ARC - monitor

Question 33

do you treat adults with strabismus?

Answer 33

prisms, lenses or surgery

Question 34

what will a 50 year old px with recent onset constant right esotropia normally experience?

Answer 34

uncrossed diplopia

Question 35

if you have a 6 year old with moderate right esotropia (ARC) can you use prisms or surgery?

Answer 35

no, they will get diplopia as they want to use their pseudofovea

Question 36

if you have a 6 year old with moderate right esotropia (suppression) can you use prisms or surgery?

Answer 36

no, they will get diplopia as they want to use their pseudofovea
but
if you have large angle strabismus consider surgery for cosmesis

Question 37

how to explain suppression to a parent and child

Answer 37

both your child’s eyes are working, however they do not work together
when both eyes are open they either use their left eye or right eye (not both)
she does not use both at the same time
this means she prob finds activities where she is required to judge distances of objects harder than other children eg. ball sports like netball, basketball etc