Axes and angles Flashcards Preview

Optics 5 > Axes and angles > Flashcards

Flashcards in Axes and angles Deck (33):
1

any two optical system is required to be aligned _________ to do efficient transmission

aligned coaxially

2

the pupil is decentered________ and the fovea is decentered_____________

Pupil: nasally
Fovea: temporally

3

what is the optical axis of the eye?

-the axis containing the centers of curvature of the eye's optical surfaces
-line of rotational symmetry

4

can purkinji images reflected from four surfaces of decentered eye be aligned?

nope

5

rotationally symmetric optical systems need one axis, which is what?

optical axis

6

what is the visual axis?

-the line connecting the foveola and the fixation point passing through the nodal points
-no chromatic aberrations

7

the place of intersection of visual axis with the cornea is called...

ophthalmometric pole

8

is the visual axis dependent on pupil position?

-nope

9

what is the pupillary axis?

the line normal to the cornea passing through the center of the pupil
-we do not care if it hits the fovea

10

what axis is good to measure the amount of eccentris fixation?

the pupillary axis

11

eccentric fixation is an adaptation to what?

heterotropia

12

what is the line of sight?

ray from fixation point that reaches the foveolar via center of the pupil

13

what is the point called where the line of sight intercepts the cornea?

corneal sighting center

14

the line of sight is a useful reference when examining what?

corneas that are undergoing refractive surgery

15

what is the achromatic axis?

-the line connecting the nodal point and the center of the pupil
-no chromatic aberrations
-DEPENDENT ON PUPIL POSITION

16

what is the fixation axis?

the line passing through the fixation point and the center of rotation of the eye
-depends on direction of rotation

17

what is the fixation axis a good reference for?

measuring eye movements

18

what is the keratometric axis?

the line passing through the fixation point and the center of curvature of anterior cornea

19

the keratometric axis is used for alignment in what?

corneal topography measurements

20

the point at which the keratometric axis intercepts the cornea is called what>

vertex normal

21

what is the photoreceptor axis?

-light arriving a the retinal plane along the photoreceptor axis will be totally internally reflected and have a higher probability of being absorbed by the photopigment

22

what is the neural axis?

increasing eccentricity declines image quality because there are less cones

23

what is angle alpha?

-angle between the optical and visual axis
-angle formed at first nodal point by the optical axis and visual axis

24

if the angle between the visual axis and the optical axis is considered to be positive when?

when the visual axis is on the NASAL side of the optical axis in OBJECT space

25

what is angle lambda?

angle between the pupillary axis and the line of sight

26

what is considered positive angle lambda?

-the pupillary axis is TEMPORAL to the line of sight in OBJECT space

27

angle lambda is important for diagnosing what?

-eccentric fixation
-heterotropia

28

what is angle kappa?

angle between the pupillary axis and visual axis

29

angle kappa is the same as what?

angle lambda

30

what is angle psi?

the angle between the visual axis and the achromatic axis
-both go through nodal points

31

what is positive angle psi?

-the visual axis is inclined NASALLY to the achromatic axis in OBJECT space

32

what is angle gamma?

the angle between the optical axis and the fixation axis

33

angle gamma is within 1% of angle alpha for object distances_______________

greater than 50cm