Optics: Pupillary Optics

Question 1

The iris has no….

Answer 1

optical power

Question 2

The iris forms the _____ ____ of the eye

Answer 2

Aperture stop

Question 3

The opening of the aperture stop(iris) is known as the ______.

Answer 3

Pupil

Question 4

What two muscles control pupil size?

Answer 4

Sphincter pupillae- pupil constriction
Dilator pupillae- pupil dilation

Question 5

The iris is designed to prevent _________ ____ from getting to the lens/retina

Answer 5

Undesirable light

Question 6

The iris is desgined to have _____ granules in stroma and epithelium (brown eyes)

Answer 6

Melanin

Question 7

Blue and green colored irises has granules in the ________.

Answer 7

Epithelium

Question 8

The iris is the ___ reliable biometric identification system

Answer 8

Most

Question 9

What are the five functions for the iris?

Answer 9

-Stops undesirable light
-Regulates retinal illumination
-Controls depth of field
-Helps in controlling retinal blur
-Help design optical instruments

Question 10

The entrance pupil EP of an optical system is the…

Answer 10

The image of the aperture stop from in the object space

Question 11

The exit pupil XP is the…

Answer 11

Image of the aperture stop formed in the image space

Question 12

Entrance pupil in eye is a ____, _____, and _______image formed 0.5 mm in front of the real pupil

Answer 12

Virtual, erect, magnified image

Question 13

What part of the iris stops undesirable light

Answer 13

Pigmented tissues

Question 14

how does the iris regulate retinal illuminance

Answer 14

Pupil size and retinal layers

Question 15

How does the iris control depth of field?

Answer 15

Makes the pupil smaller

Question 16

How does the iris help control retinal blur

Answer 16

Diffraction and aberrations

Question 17

How does the iris help design optical instruments

Answer 17

Entrance pupil and exit pupil

Question 18

Exit pupil is _____mm behind the real pupil and ____% larger than the real aperture

Answer 18

0.07mm
3.1% larger

Question 19

The level of ____ is the most important factor affecting pupil size

Answer 19

Illumination

Question 20

The pupil response to an increase in illumination is to ____ the pupil size

Answer 20

Decrease

Question 21

With low illumination, there is a latency of ____ seconds before constriction of pupil

Answer 21

0.5 seconds

Question 22

With increased illumination, the latency decreases to ____ seconds

Answer 22

0.2 to 0.3 seconds

Question 23

Pupil response to full withdrawal of light may take up to a ____

Answer 23

A minute

Question 24

The pupil has more response when light distribution is in the ____ visual field

Answer 24

Central visual field

Question 25

The pupil has less response when light distribution is in the ______ visual field

Answer 25

Peripheral visual field

Question 26

Pupil response to changes in light level is mediated by both ___ and ____ photoreceptors

Answer 26

Rod and cone

Question 27

Direct light reflex

Answer 27

The constriction of the pupil due to direct light simulation

Question 28

Consensual light reflex

Answer 28

Pupils of both eyes respond equally to stimulation of only one eye

Question 29

Near reflex

Answer 29

The pupil decreases in diameter when the eyes converge or accommodate

Question 30

Pupil centration

Answer 30

Pupil is decentered by 0.5mm nasally relative to the optical axis

Question 31

As age increases, pupil size _____

Answer 31

Decreases ( senile miosis)

Question 32

Mydriatics affect on pupil

Answer 32

Simulates sympathetic nervous system dilates the pupil

Question 33

Miotics affect on pupil

Answer 33

Stimulates parasympathic system, constricting the pupil

Question 34

Pleasant mental images affect on pupil

Answer 34

Increases pupil size

Question 35

Unpleasant mental images affect on pupil size

Answer 35

Decreases pupil size

Question 36

To increase the depth of field, the pupil will _____.

Answer 36

Decrease in size

Question 37

Depth of field is the range of distance over which the system’s detector….

Answer 37

Cannot detect any change in focus

Question 38

DoF for the human eye is between ___D to ___D

Answer 38

0.5 to 1

Question 39

If you observe someone’s pupil from oblique angels, you will see that

Answer 39

The pupil becomes narrower in the direction of view

Question 40

The apparent area of the pupil decreases as the oblique viewing angle is ______

Answer 40

Increased

Question 41

The decreases in diameter with viewing angle has two important implications:

Answer 41

1. The oblique aberrations and hence retinal image quality 2. The amount of light entering the eye from oblique angles, and hence the brightness of a peripheral retinal image

Question 42

Light entering the eye and reaching the fovea depends on the ____ ____ of the pupil

Answer 42

Entry point

Question 43

Light entering the eye near the center of the pupil appears ____ than light entering near the edge

Answer 43

Brighter

Question 44

For ______ pupil diameters, aberrations cause deterioration in retinal image quality

Answer 44

Large

Question 45

For _____ pupil diameters, diffraction limits image quality

Answer 45

Small

Question 46

The optimum pupil diameter is

Answer 46

2-3mm

Question 47

To get maximum field of view when looking through an eyepiece into an eye, you have to align the eye’s ______ pupil with the external system’s _____ pupil

Answer 47

Entrance, exit