Vision

Question 1

Objectives of development of binocular vision: Acquiring foveal centration:

Answer 1

• Acquiring foveal centration:

- Acquiring the ability to accommodate the lenses to near vision

Question 2

Acquiring foveal centration:

Answer 2

a. Acquired ability to fix the fovea centralis of each eye on the same target
b. Fovea centralis is about 1.5 mm in diameter
c. Area of max visual acuity covers about 3 degrees of visual field

Question 3

conjugate (yoked) eye movements

Answer 3

necessary for development of binocular vision and depth perception. Presented around ages 4 months.

Question 4

Yoked (Con/ Di) vergence movements

Answer 4

yoked convergence and divergence movements. Usually presented at 6 months.

Question 5

Lens accommodation for near vision.

Answer 5

This keeps near objects in focus, infants are slightly hyperopic/ slight far sighted and usually occurs at the age of 6 months. They need to learn lens accommodation for near vision

Question 6

Hyperopia: far sighted

Answer 6

Ciliary muscles relax for far vision
Ciliary muscles contracts to accommodate for near vision
Desired results: Emmetropia

Question 7

Concurrent requirement: appropriate cortical mapping: wire together, fire together

Answer 7

• it is activity driven:
  a. lateral geniculate nuclei (LGN) in the thalamus
  b. ocular dominance columns and cortical mapping

Question 8

Ocular dominance columns should be?

Answer 8

balanced from side to side

Question 9

cortical mapping: balancing these columns is a learned?

Answer 9

activity driven sorting process

Question 10

cortical mapping: balancing these columns is key?

Answer 10

to future development of visual system

Question 11

some evidence of this balancing should be seen by?

Answer 11

4-6 months of age

Question 12

What is the eventual outcome of a lack of balance?

Answer 12

1. This process is developmental and it is sometimes hard to predict the outcome and 2. The perfect balance can be very hard to achieve and very hard to maintain
   reality: almost everyone has a dominant eye

Question 13

Assessing corneal light reflections

Answer 13

Corneal light reflections from ambient light should land in the same clock position in each eye.

Question 14

Evaluating accommodation and the accommodative triad

Answer 14

accommodative convergence, accommodative pupillary constriction and accommodation of lens for near vision

Question 15

convergence/ accommodative break

Answer 15

one eye deviates back to the original starting position as the pencil approaches the nose

Question 16

Convergence insufficiency self test

Answer 16

the patient looks at center vertical line as the paper is brought towards their nose from a distance of about 18’’. What’s normal? The center line remains in focus at about 5’’

Question 17

Convergence insufficiency self test: abnormal

Answer 17

convergence insufficiency, a double image of that line is seen as the paper nears the eye

Question 18

Strabismus

Answer 18

an eye is deviated when both eyes are open

Question 19

Tropia (L “a turning”)

Answer 19

T for turn

Question 20

Phoria (L “a bearing”

Answer 20

an eye that deviates only when it is covered an it’s visual stimulus is taken away

Question 21

Cover- uncover test

Answer 21

looks for evidence of phoria, an eye deviates only when an eye is covered and losses it’s visual input.

Question 22

Cardinal fields of gaze

Answer 22

evaluating fixation and pursuit movements

Question 23

Cardinal fields of gaze test Steps:

Answer 23

o 1: fixation, inability to fix gaze on stationary target can imply a serious disorder
o 2: pursuit, inability to smoothly peruse a moving object can be found with a number of different disorders

Question 24

Normal variants on cardinal fields of gaze:

Answer 24

1. Hyper dominant eye

2. Physiologic end point nystagmus of brief duration

Question 25

variants on cardinal fields of gaze: Abnormal: undershoot or overshoot

Answer 25

1. may be seen with cerebral disease

2. may be seen with acute alcohol intoxication

Question 26

variants on cardinal fields of gaze: Abnormal: jittery eye movements

Answer 26

might be an early indication of MS

Question 27

variants on cardinal fields of gaze: Abnormal: lesions of vestibular/ oculomotor /cerebral systems

Answer 27

1. Spontaneous nystagmus with no apparent cause: newly acquired? Congenital?
2. Gaze evoked nystagmus: fixation or pursuit results in a very irregular nystagmas
3. Tropias that occur during pursuit movements- differential: benign paroxysmal positional vertigo