Ocular Motility: Lecture 13: Eye Movements During Reading

Question 1

1. What do fixations refer to?
   a. What happens if the material is more difficult?
   b. Or if someone is a Poor reader?

Answer 1

1. Total number of “Eye Stops” or pauses of the eyes during reading.
   a. More fixations are made
   b. Make more fixations than good readers

Question 2

1. When eyes move from 1 fixation point to another, how is it done?
   a. Type of movement and degrees of movement?
2. As word length increases, probability of fixating that word increases/decreases?

Answer 2

1. Left-to right progressive saccades
   a. Or via Interfixation Movements of 1 to 2 degrees
2. Increases; BU, most words are only fixated ONCE!

Question 3

1. What is the average saccade length?
   a. What is the range?
   b. Percent of total reading time taken up by the actual eye movements is what?
   c. What’s the average?

Answer 3

1. 8 Characters
   a. 1-18 Characters
   b. 10%
   c. 7%

Question 4

1. What are REGRESSIONS?
   a. What is the size (character wise)?
   b. Who tends to make a ton of regressions?
   c. Normally: what % of Saccades (fixations) are regressive?
   d. What words are REFIXATED more than others?

Answer 4

1. Fixations that are directed from Right-to-Left by “Backward” or regressive movements during reading
   a. A Few characters in Extent and typically reflect some text confusion or Comprehension Problem
   b. Children learning to Read or Poor Readers
   c. 10-15%
   d. Uncommon words are more refixated than Common words

Question 5

1. What is a Return-Sweep Saccade?
   a. What is their Typical Angular Extent in Degrees?
   b. Normal Duration time?

Answer 5

1. LARGE Right-to-Left, Slightly Oblique, Saccadic Eye Movement, that shifts the eyes from Near the End of one Line to near the beginning of the next line of TEXT
   a. 12-20 degrees in angular extent
   b. 40-54 msec

Question 6

1. Recognition is Specified in UNITS of what?

a. How is it calculated?

Answer 6

1. of WORDS!

a. by dividing the number of fixations into the number of words in the specified paragraph

Question 7

1. What is Perceptual Span?
   a. Is it Symmetric or Asymmetric?
   b. How many characters to the left does it Extend?
   c. And to the Right of the fixation point?

Answer 7

1. MAXIMUM EFFECTIVE TEXT PROCESSING FIELD during a Fixation
   a. Asymmetric

b. 4
c. 15

Question 8

1. What does Fixation Duration refer to?

a. Average fixation duration?

Answer 8

1. Length of Time (usually in millisecs) that the eye pauses or remains fixated on a word
   a. About 225 msec

Question 9

1. What does Reading Rate refer to?

a. Avg college student reading rate?

Answer 9

1. Number of Words read per unit time and is usually specified in WPM
   a. 200 to 350 wpm

Question 10

1. Each dot represents what?

2. Each Interconnecting Line represents what?

Answer 10

1. Fixation Site
2. Saccadic Trajectory
   * There’s a correlation b/w Text Length/Spacing and the Overall Eye movement Pattern

Question 11

Foveal and Parafoveal Reading

1. What 2 regions are CRUCIAL for the Reading Process?
   a. Central Retina has to be used for basic Visual Resolution of the Text Letters. Why?

Answer 11

1. Foveal (+/- 1 degree) and Parafoveal (+/- 5 degrees)
   a. because beyond a few degrees it’s too reduced to be effective.
   * So the 1-2 degree left-to-right reading saccades take place to resolve and then process the fixated letter groups

Question 12

Foveal and Parafoveal Reading (2)

1. As MASKING SIZE INCREASED, what happens?
2. Overall reading performance (both objectively and subjectively) is is WORSE in what condition?

Answer 12

1. Fixation duration increased, saccade length generally increased, total number of fixations increased, and READING RATE DECREASED
2. is WORSE in the FOVEAL MASKING CONDITION

Question 13

1. What processing are the FOVEA and the NEAR PARAFOVEA involved in?
   a. What is the FAR PARAFOVEA Primarily used for?

Answer 13

1. SEMANTIC PROCESSING

a. to guide Eye movements to the Next Fixation Location

Question 14

1. If a SCOTOMA is at either side of the fovea (stimulating Hemifield Loss), what happens to the READING RATE?
   a. When is this effect worse?
   b. What is a Scotoma is located above or below the Fovea?

Answer 14

1. It’s Impaired, despite the presence of Normal Foveal Viewing
   a. When the SCOTOMA is Located to the RIGHT (50% decrease in reading rate) of the FOVEA, because it interferes w/left-to-right sequencing of all progressive saccades
   b. No Adverse Effects are Noted

Question 15

Abnormal Reading Eye Movement: What are they?

Answer 15

1. Aniseikonia
2. Anisometropia
3. Binocular Suppression
4. Convergence Insufficiency
5. High Near Phoria (especially Exophoria)
6. Large Fixation Disparity
7. Poor Binocular Coordination
8. Poor Fusional Ability
9. Receded Near Point of Convergence
10. Strabismus (especially Intermittent)

Question 16

Dyslexia

1. What do slow readers tend to make more of than Normal readers?
   a. What about Amplitudes?
2. What happens in Dyslexics?

Answer 16

1. More forward and Regressive movements
   a. Amplitude of Regressions is ALSO SMALLER than the Preceding forward Saccades
2. Regressions are VERY FREQUENT and tend to happen in CLUSTERS OF TWO OR MORE
   a. AMPLITUDE is frequently BIGGER than that of the PRECEDING FORWARD SACCADE!

Question 17

Dyslexia (2)

1. What are the 2 categories of Dyslexia?
   a. Which one is most commonly encountered?
   i. What does this refer to?

Answer 17

1. Developmental (Congenital) and Acquired
   a. Developmental
   i. to the Occurrence of a specific reading disability, that’s at least 2 years behind expected grade level of reading in the presence of normal intelligence and sensory vision and in the absence of neurologic and emotional disorders

Question 18

1. Language Deficit Dyslexia
   a. Tends to show an increased number of what 4 thigns?

b. What happens if they are given text that is appropriate to their reading level?

Answer 18

1. a. Increased number of Progressive and Regressive Movements, Small-Amplitude Saccades, and Prolonged Fixation Durations when reading text appropriate for their age level.
   b. The overall reading pattern tends to Normalize

Question 19

1. Visual-Spatial Dyslexia
   a. What is it?
   b. What does this include?

Answer 19

1. a. Inaccuracy of the Return-Sweep Saccade, and FREQUENT right-to-left Sequences of Saccades
   b. This includes Partial and Complete “reverse staircase” patterns, where the series of saccades traverses some or all of the line of print, respectively, independent of the level of reading material.

Question 20

1. Acquired Dyslexia
   a. What does it refer to?

b. First complaint reported?
c. peeps who have this w/o basic abnormal oculomotor control, reading patterns are like that of a person with what?

Answer 20

1. a. the presence of a reading disability in a previously normal reader subsequent to neurologic dysfunction or damage, like a stroke
   b. Reading difficulty; Including reduced comprehension, difficulty in sequencing of eye movements, problems w/maintenance of fixation, and the necessity to move the head to assist reading
   c. w/developmental language-deficit Dyslexia will be found.

Question 21

Central Neurologic Disorder

1. What does it produce?
2. What becomes more difficult?

Answer 21

1. Square-Wave Jerks, Jerk and Pendular Nystagmus, and Slowed Saccades
2. Ability to maintain steady fixation as well as to change fixation to a new word accurately and efficiently.

Question 22

Nystagmus and Reading

1. What happens to Nystagmus slow phases during Intended Steady Fixation?
2. What happens to Reading rate?

Answer 22

1. Exponentially increasing nystagmus slow phases

2. reduced (115-150 wpm)

Question 23

Fundus Flavimaculatus

1. Patients w/Central Scotomas tend to use what?
   a. Why?
2. The Objective Eye Movement Record for Stimulated reading shows what kind of saccades?
   a. What does this suggest?

Answer 23

1. a SINGLE ECCENTRIC RETINAL LOCUS on the Superior Edge of the Scotoma for fixation
   a. So the field below their gaze is available to assist in all tasks, ESPECIALLY WALKING and READING
2. Numerous Vertical Saccades
   a. Difficulty in localizing the words w/the eccentric retinal Locus, as well as a somewhat irregular overall pattern