Visual Acuity

Question 1

Types of Visual Acuity

Answer 1

1. Detection Acuity
2. Resolution Acuity
3. Localization Acuity
4. Letter or optotype acuity

Question 2

Detection

Answer 2

spot or not?

Question 3

Resolution

Answer 3

two or one?

Question 4

Localization

Answer 4

Vernier (two lines aligned?)

Question 5

Letter

Answer 5

discrimination/orientation of the letter

Question 6

Quickest Acuity Task

Answer 6

1. Detection of Bright Line or Spot
2. Detection of Single Dark Line
3. Vernier Lines

Question 7

Longest Acuity Task

Answer 7

1. Optotype
2. Resolution of Two Dark Lines
3. Grating

Question 8

Point Spread Function

Answer 8

Relative luminance profile of the retina (curved not straight lines)

Question 9

Smallest Detectable Line

Answer 9

0.5 - 1 arc sec

Question 10

Smallest Detectable Dot

Answer 10

15 arc sec

Question 11

A cycle

Answer 11

a pair of dark and bright bars

Question 12

Period

Answer 12

width of the cycle (deg)

Question 13

Spatial Frequency

Answer 13

1/period (c/deg)

Question 14

Designation of Optotype Acuity

Answer 14

1. Snellen
2. Decimal
3. MAR
4. LogMAR

Question 15

Factors Affecting Acuity

Answer 15

1. Blur
2. Selection of Target
3. Target Spacing
4. Contrast
5. Luminance
6. Retinal Ecc
7. Image Motion
8. Target Duration

Question 16

Blur-Acuity

Answer 16

Blur degrades letter acuity much more than grating acuity