Monochomatic Aberrations Of The Human Eye Flashcards
What does defocus depend in
Pupil size and Rx
How much defocus can make a big difference
0.25 microns
What does trefoil look like.
3 POINTS
Is trefoil bad
Not as bad as others, a lot of light still focused in the center
Coma
Off axis defocus
- seen in keratoconus
- thin corean after LASIK
Spherical aberrations
Not focusing on same spot
E in spherical aberrations
Faint but can still see E, negative would be even better
What is the aberration that does not have a nonzero value
Spherical
A population average of the magnitude of zernike terms
Shows that higher order aberrations are dominated by 3rd order and spherical aberrations
Aberrations and pupil size
Aberrations reduced with reduced pupil size
Dynamic changes in the wave aberrations are caused by
Accommodation
Eye movement
Eye translation
Tear film
What is LASIK mainly good for
Defocus and cyl
Primary sources of scattered light
Cornea
Iris/sclera
Lens
Fundus
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
Wavefront for LASIK
Central flat area and curvature in peripheral
Post LASIK wavefront
Spherical looking
Change in aberration over age
Not a big change over age
How will having a smaller optical zone change the depth of incision
Won’t need to go as deep with a smaller optica zone
For an 8mm pupil, how many microns do you need to -1.00D in LASIK
1
For a 2mm pupil, how many microns do you need to get to -1.00D?
0.12microns
Problems with a small optical zone
Probably worse vision, especially at night
