10 - Opth - Squints - Orthoptics + Types of Squint

Question 1

Define binocular vision

Answer 1

using two eyes as a pair to perceive one image

Question 2

3 grades of binocular vision

Answer 2

Simultaneous perception - by each eye
Fusion - two images fuse to make one, which is maintained with movement
Stereopsis - fused images are seen in depth

Question 3

define squint

Answer 3

strabismus

deficit of controlled eye movement

Question 4

2 classifications of squints

Answer 4

manifest OR latent

concomitant OR incomitant

Question 5

Manifest squint

• features
• suffix
• detection

Answer 5

obvious deviation of eye, visual axis not normally aligned

• tropia
• may be obvious or detected using cover/uncover test

Question 6

Latent squint

• features
• suffix
• detection

Answer 6

tendency of eyes to deviate- normally aligned
-phoria
detect using alternate cover test

Question 7

which way is the abnormal eye pointing for these manifest squints

• esotropia
• exotropia
• hypertropia

Answer 7

eso - inward
exo - outward
hyper - upwards

Question 8

concomitant squint- what and who

Answer 8

remains the same in size and direction in all positions

more common in childhood

Question 9

Incomitant squint - what + why + when most obvious

Answer 9

changes in different positions of gaze
under action of at least one of the extraocular muscles
most obvious when gaze directed toward affected muscles

Question 10

2 consequences of squints

Answer 10

diplopia - common if squint develops after visual development (>7y)
suppression - esp if <7y - may lead to amblyopia

Question 11

Amblyopia - causes?

Answer 11

stimulus deprivation
strabismic (squint)
anisometropic (higher refractive error in one eye)

Question 12

Amblyopia - mgmt?

Answer 12

can be treated <7y
Tx - occlusion of good eye with patch ~ 6 hours a day

Tx - correction of squint