What Limits Vision

Question 1

What is the limit of human retina

Answer 1

300 pixels/inch

Question 2

Which PSF corresponds to a small pupil?

Answer 2

Large airy disc

Question 3

Between vision is achieved with
A. With a more confined PSF
B. With a less confined PSF
C. PSF size doesn’t matter

Answer 3

With a more confined PSF

Question 4

The we consider diffraction only, better vision is achieved with

Answer 4

Larger pupil

Question 5

PSF without aberrations would be what

Answer 5

Airy disc

Question 6

Aberrations and pupil size

Answer 6

Get worse with larger pupil

Question 7

Larger pupil with diffraction only

Answer 7

Increased VA

Question 8

Aberrations and pupil size

Answer 8

Worse with larger pupil

Question 9

What is the sweet spot for diffraction and aberration

Answer 9

2-3mm pupil

Question 10

Pupil-dependent limit to vision

Answer 10

About 1 arcmin

Question 11

What is not taken into consideration when talking about retinal display

Answer 11

Viewing display

Question 12

The required pixel density to meet the criterion for retinal display

Answer 12

Varies depending on size of display

Question 13

What kind of screen has potential to be a retinal display?

Answer 13

Any if at the right distance

Question 14

Resolution limit for the standard vision human eye

Answer 14

1 arcmin

Question 15

Pixel density for retinal display

Answer 15

1 pixel per 88microns, over an inch, 288 pixels make it 300

Question 16

What part of the eye os responsible for image formation?

Answer 16

Cornea, lens, pupil

Aberrations and diffraction

Question 17

Image collection and recording in eye

Answer 17

Retina (photoreceptors)

Question 18

What is the average cone spacing in fovea

Answer 18

2.6microns, 0.5 arcmin

Question 19

Cone spacing

Answer 19

Rods and cones behave differently and aren’t dispersed evenly

Question 20

With half the photosensor pixel size, resolution is

Answer 20

Double

Question 21

What signal do we perceive

Answer 21

Analog

Question 22

What signal do we send to the brain

Answer 22

Digital

Question 23

Limitations imposed by cone signaling

Answer 23

If the signal has more dense info, this wont be picked up

Sensor spacing=cone spacing (fovea)

Question 24

Digital sampling limit to vision

Answer 24

0.5 arcmin

Question 25

What do you control with pinhole

Answer 25

Depth of field

Question 26

What are the two jobs of pinhole

Answer 26

1. Sweet spot

2. Increase depth of focus

Question 27

What does pinhole ultimately do

Answer 27

Aberration and diffraction still there, but all these effects are least possible with pinhole

Question 28

What does pinhole visual rule out

Answer 28

Pathology

Question 29

Diffraction effects due to a small pinhole contribute to what

Answer 29

• Increase of the size of the circle of least confusion
• increases the range of acceptable vision (depth of focus)
• reduces effects of aberrations

Question 30

Pinhole occluder said with a _____ aperture are used during routine ocular examination to benchmark the potential for best refractive visual correction

Answer 30

1.2mm

Question 31

The pinhole allows individuals with a refractive error up to _______ to see up to ______ logMar

Answer 31

5 diopter

0.17 logMAR