Optics Lecture 2

Question 1

How must receptor units be placed to resolve fine details of the pattern imaged on the retina

Answer 1

Sufficiently close together to correctly interpret the pattern

Question 2

When the visual system correctly interprets the spatial frequency and orientation of pattern

Answer 2

Veridical

Question 3

Spatial frequency at which finest light pattern that can be correctly resolved by the retina

Answer 3

Nyquist limit

Question 4

The nyquist limit of the human visual system

Answer 4

60c/deg

Question 5

The spatial frequency at which the visual system cannot distinguish between light patterns

Answer 5

Aliasing

Question 6

The spacing of what cells limit resolution

Answer 6

Ganglion cells

Question 7

Why are PR not a limiting factor for visual resolution

Answer 7

Because peripheral cones are spaced too closely

Question 8

If only considering neural blur, can contrast be better than 60 c/deg

Answer 8

Yes

Question 9

If considering optics and neural blur, can contrast be better than 60 c/deg

Answer 9

No

Question 10

With laser interferometry, how does the contrast sensitivity change

Answer 10

It increases form 60 to 120 c/deg

Question 11

The 2 major spatial tasks performed by human system

Answer 11

Resolution and detection

Question 12

Do gang cells increase or decease away from fovea

Answer 12

Decrease

Question 13

Detection in the central and peripheral vision is limited by

Answer 13

Size of cones

Question 14

Resolution and detection at fovea

Answer 14

Patters reliably resolved and detected

Question 15

Resolution and detection at peripheral (30 deg nasal)

Answer 15

Reliably detect but not resolved

Question 16

Between detection and resolution is called

Answer 16

Aliasing

Question 17

3 steps of letter recognition

Answer 17

Detection
Resolution
Identification

Question 18

Reasons for discrepancy on central visions impact on retinal image quality

Answer 18

• Overestimation bc scattering is being ignored

- emphasis on MTF (ignore PTF)

Question 19

Most important optical defect affecting retinal image quality is

Answer 19

Defocus

Question 20

Polychromatic light impact on retinal image quality: max contrast sensitivity loss of ______ and a visual acuity loss of _____

Answer 20

.2 log unit

10 %

Question 21

TCA causes loss of

Answer 21

Image contrast

Question 22

What is the stiles-Crawford effect on retinal image quality

Answer 22

Influence optimal refraction in presence of aberrations, but the magnitude is likely to be small

Question 23

The luminous efficiency of rays entering at the center of the pupil is (>/

Answer 23

Greater than

Question 24

Influences the VA and visual performances of the eye

Answer 24

Stiles - Crawford apodization

Question 25

How does pupil decentration affect retinal image quality

Answer 25

Induces additional aberrations, like TCA, which decrease spatial visual performance

Question 26

How does retinal image quality change with object angle

Answer 26

It steadily declines