Optics Lecture 4 Flashcards Preview

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Flashcards in Optics Lecture 4 Deck (20):
1

Can we prescribe refractive correction from wf measurements

No

2

Gold standard method of refraction

Clinical phoroptor method

3

Give the comprehensive description of eyes optical aberrations from which the retinal image can be computed using the theory of physical or geometrical optics

Shack-Hartmann aberrometry

4

What types of aberrations to we fix w/o surgery

Astigmatism and defocus

5

How do we correct HO aberrations

Surgery

6

How are subjective a objective refraction different in terms of chromatic aberrations

By wavelength used
- Obj - IR light
- sub - white light

7

How are subjective a objective refraction different in terms of stiles-Crawford effect

PR are fine tuned toward center of pupil
- light from periphery isnt caught by cones

8

How are subjective a objective refraction different in terms of max plus technique

Obj - give max +
Sub - give mean

9

How are subjective a objective refraction different in terms of measurement plane of the instrument

Sub - spectacle place
Obj - corneal plane

10

What must you do to compare obj (wf) with sub (va)

Make all factors the same
- wavelength
- Pupil size
- Plane of measure
- Accommodation
- Measurement technique

11

What is the population mean for subjective refraction for 3mm pupil

.19D

12

What is the population mean for subjective refraction for 6mm pupil

.23D

13

Does the refractive error for subjective method change when the pupil dilates

No

14

What is the population mean for objective refraction for 3mm pupil

Hyperopic relative to subjective mean

15

What is the population mean for objective refraction for 6mm pupil

Myopic relative to subjective

16

When HO aberration are small, how do all of the metrics relate

They are the same

17

When HO aberrations are large, how do all the metrics relate

Different metrics give different refraction

18

Are many objective refracts accurate/precise

Yes

19

Is zernike accurate and precise

No, too myopic

20

Is paraxial accurate/precise

No, too hyperopic