Physical and Optical Characteristics

Question 1

Image Vergence

Answer 1

V = U + P

= object vergence + power

Question 2

Real Image

Answer 2

exiting light with a positive vergence

Question 3

Virtual Image

Answer 3

exiting light with a negative vergence

Question 4

Real Object

Answer 4

incident light with negative vergence

Question 5

Virtual Object

Answer 5

incident light with positive vergence

Question 6

Paraxial Approximation

Answer 6

incident rays are close to optical axis

yields point image for point objects

Question 7

Optical Axis

Answer 7

where light passes through undeviated

line joining 2 centers of curvature of a lens

Question 8

Axis of Rotation

Answer 8

perpendicular to muscle plane that eye moves around

Question 9

Lens Effectivity

Answer 9

change in vergence of light

Question 10

2 lenses have the same lense effectivity if…..

Answer 10

make a real or virtual image at the same point

Question 11

Marginal Rays

Answer 11

rays on periphery, far from optical axis

Question 12

Paraxial Rays

Answer 12

rays in close proximity to optical axis

Question 13

Aperture Stop

Answer 13

limits amount of light passing into an optical system

Question 14

Field Stop

Answer 14

limits size of object that can be imaged by system

Question 15

Depth of Focus

Answer 15

interval surrounding retina where an eye sees an object in focus

Question 16

Short focal length =

Answer 16

large depth of field

Question 17

Depth of Field

Answer 17

interval surrounding fixation plane where an object can be in focus

Question 18

Increase aperture size =

Answer 18

decreased depth of field and focus

Question 19

Aberrations

Answer 19

create optical distortions in image plane

Question 20

Monochromatic Aberrations

Answer 20

wavelength independent aberrations

spherical, coma, radial astigmatism, curvature of field, distortion

Question 21

Chromatic Aberrations

Answer 21

longitudinal and transverse

Question 22

Spherical Aberration

Answer 22

peripheral rays focus at different points on optical axis than paraxial rays

Question 23

Longitudinal SA

Answer 23

length of blur circle

marginal and paraxial rays focused at 2 different places

Question 24

Lateral SA

Answer 24

area size of blur circle

Question 25

Increase in pupil size _____ image quality

Answer 25

decreases | more aberrations

Question 26

Coma

Answer 26

comet shaped | from various magnification in height of incident rays

Question 27

Aberrations cancelled by small pupil size

Answer 27

spherical aberration and coma

Question 28

Necessary to compensate for spherical aberration

Answer 28

very high powered lenses

Question 29

Influence effective power of a lens

Answer 29

vertex distance- increase- more minus; decrease- more plus | rays at oblique angle- makes astigmatism and spherical

Question 30

Oblique Astigmatism

Answer 30

from rays hitting lens obliquely causing power to be altered | warped image plane

Question 31

Difference between sagittal and tangential power

Answer 31

oblique astigmatism

Question 32

Curvature of Field and Oblique Astigmatism

Answer 32

different warping along two principal axis

Question 33

Petzval Surface

Answer 33

image surface created by a system with no OA

Question 34

When is the curvature of field present?

Answer 34

when Petzval surface does not correspond to the far point of the eye

Question 35

Corrected Curve Lenses

Answer 35

lenses corrected for OA, curvature of field, or both

Question 36

Point Focal Lense

Answer 36

lens corrected completely for radial astigmatism | curvature of field uncorrected

Question 37

Percival Form Lens

Answer 37

lens corrected completely for curvature of field | OA uncorrected

Question 38

Distortion

Answer 38

straight line objects that do not pass through the optical axis- curved

Question 39

Distortion is more of a problem in....

Answer 39

higher powered lenses

Question 40

Aberrations causing the most concern

Answer 40

OA Curvature of Field Distortion

Question 41

Higher refractive index = ________ lens

Answer 41

thinner

Question 42

Longitudinal Chromatic Aberrations

Answer 42

different wavelengths are focused at different distances from lense

Question 43

Transverse Chromatic Aberrations

Answer 43

different wavelengths are focused at different points in same focal plane blue light deviates the most

Question 44

Red-Green test is based on....

Answer 44

chromatic aberrations

Question 45

Chromatic Dispersion

Answer 45

quantifies the amount of chromatic aberration in a lens

Question 46

Effects of Transverse Chromatic Aberration

Answer 46

impacts peripheral viewing prismatic effects for different wavelengths greater impact at higher powers, but need a lot to cause issues

Question 47

Minimizing Chromatic Aberrations

Answer 47

shorter vertex distance monocular PDs add sufficient panto

Question 48

Abbe Number

Answer 48

Bigger is better | higher index of refraction = lower number