Monochomatic Aberrations Of The Human Eye Flashcards Preview

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Flashcards in Monochomatic Aberrations Of The Human Eye Deck (21)
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1

What does defocus depend in

Pupil size and Rx

2

How much defocus can make a big difference

0.25 microns

3

What does trefoil look like.

3 POINTS

4

Is trefoil bad

Not as bad as others, a lot of light still focused in the center

5

Coma

Off axis defocus
-seen in keratoconus
-thin corean after LASIK

6

Spherical aberrations

Not focusing on same spot

7

E in spherical aberrations

Faint but can still see E, negative would be even better

8

What is the aberration that does not have a nonzero value

Spherical

9

A population average of the magnitude of zernike terms

Shows that higher order aberrations are dominated by 3rd order and spherical aberrations

10

Aberrations and pupil size

Aberrations reduced with reduced pupil size

11

Dynamic changes in the wave aberrations are caused by

Accommodation
Eye movement
Eye translation
Tear film

12

What is LASIK mainly good for

Defocus and cyl

13

Primary sources of scattered light

Cornea
Iris/sclera
Lens
Fundus

14

Actual subjective appearance of straylight: a pattern of very fine streaks, not at all like the circularly uniform scattering pattern of particles of approximate wavelnegth size

Ciliary corona

15

Wavefront for LASIK

Central flat area and curvature in peripheral

16

Post LASIK wavefront

Spherical looking

17

Change in aberration over age

Not a big change over age

18

How will having a smaller optical zone change the depth of incision

Won't need to go as deep with a smaller optica zone

19

For an 8mm pupil, how many microns do you need to -1.00D in LASIK

1

20

For a 2mm pupil, how many microns do you need to get to -1.00D?

0.12microns

21

Problems with a small optical zone

Probably worse vision, especially at night