Retinoscopy

Question 1

objective refraction

Answer 1

-determining refractive status without input by the patient

Question 2

What are the three types of objective refraction?

Answer 2

• retinoscopy
• autorefraction
• photorefraction

Question 3

Autorefraction

Answer 3

• no evaluations of patient of clinician

- no judgement from operator

Question 4

Photreception

Answer 4

-photo or video graph of pupils interpreted by trained clinician or instrument

Question 5

what does retinoscopy rely on?

Answer 5

1. the eye is a closed optical system
2. image detection during subjective refraction effectively occurs at outer limiting membrane
3. reflection of light from inside the eye produces a fundus reflex
4. effective occular reflecting surface for visible light is also at the out limiting membrane

Question 6

what does all this limiting membrane stuff mean?

Answer 6

• where the patient interprets the light is where we see the light reflected
• we dont have to ask, we can see it

Question 7

why do we do retinoscopy?

Answer 7

1. starting point for subjective refraction
2. independent objective confirmation of subjective results
3. may be heavily relied on to determine prescription for patients that cant talk to us

Question 8

how do you determine if spherical of astigmatic?

Answer 8

• is reflex the same in all meridians?(spherical)

- if different reflex, astigmatic. determine the two principal meridians

Question 9

what meridian do you netrualize if spherical?

Answer 9

-any

Question 10

if you see with motion, what lens should you neutralize with?

Answer 10

-add plus lenses

Question 11

if you see against motion, what lens should you neutralize with?

Answer 11

-add minus lenses

Question 12

how do you determine working distance?

Answer 12

• measure length from scope to eye

- 1/meters

Question 13

once you stop seeing motion, are you done?

Answer 13

• nope

- add a minus working distance

Question 14

endpoint of retinoscopy

Answer 14

-when patient’s farpoint coincides with aperture of retinoscope

Question 15

will the same lenses be used and get the same endpoint with different doctors?*****

Answer 15

-MUST CORRECT FOR SPECIFIC WORKING DISTANCE

Question 16

static retinoscopy

Answer 16

• moving farpoint to the retinoscope

- use lenses

Question 17

direct retinoscopy

Answer 17

• move retinoscope to far point of patients eye

- usually special circumstance/kids

Question 18

why is fundus reflex red/orange

Answer 18

–reflected from retina

Question 19

bracket

Answer 19

• neutrality is a range of uncertainty between perceptible “with” and “against” motion
• between absolute yes and absolute no

Question 20

six aspects of reflex

Answer 20

1. brightness
2. direction of motion
3. speed of motion
4. width
5. definition
6. alignment

Question 21

six aspects of reflex as you get closer to neutrality

Answer 21

1. brighter
2. motion decreases
3. speed increases
4. width narrows
5. difinition increases
6. becomes more aligned with streak

Question 22

speed increases when you get closer to neutrality???

Answer 22

• yea.

- it moves so fast it looks like there is no motion

Question 23

in general fundus reflex…

Answer 23

-gets easier to read as you get closer to neutrality

Question 24

abnormal fundus reflex

Answer 24

• some portions may behave different than others
• due to higher order aberrations
• scissors motion

Question 25

What do you do when you have abnormal fundus reflex?

Answer 25

- pay attention to the reflex in the center and ignore the rest - bracket, bracket, bracket

Question 26

should you allow accommodation in static retinoscopy?

Answer 26

- no! | - should be relaxed

Question 27

fogging

Answer 27

- add more plus than they need to avoid accomodation - target is blurred, but its okay cause you have a big target - second eye is still fogged by working distance

Question 28

how can you tell they are fixating on the target and not the retinoscope?

Answer 28

- pupils will get smaller | - all of a sudden change of motion without adding lenses

Question 29

potential problems with retinoscopy

Answer 29

1. examiner too far to the side 2. too many reflections 3. accommodation

Question 30

what do you hope to get out of retinoscopy?

Answer 30

-consistent objective measurement

Question 31

results should be...

Answer 31

-repeatable within +- 0.5D in each meridian and +- degree of axis

Question 32

consistant bias????

Answer 32

- consistent hyperopic bias in young patients | - youll get a little more plus