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Methods Block 3 > Retinoscopy > Flashcards

Retinoscopy Flashcards

1
Q

objective refraction

A

-determining refractive status without input by the patient

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2
Q

What are the three types of objective refraction?

A
  • retinoscopy
  • autorefraction
  • photorefraction
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3
Q

Autorefraction

A
  • no evaluations of patient of clinician

- no judgement from operator

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4
Q

Photreception

A

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

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5
Q

what does retinoscopy rely on?

A
  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
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6
Q

what does all this limiting membrane stuff mean?

A
  • where the patient interprets the light is where we see the light reflected
  • we dont have to ask, we can see it
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7
Q

why do we do retinoscopy?

A
  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
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8
Q

how do you determine if spherical of astigmatic?

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

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

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9
Q

what meridian do you netrualize if spherical?

A

-any

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10
Q

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

A

-add plus lenses

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11
Q

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

A

-add minus lenses

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12
Q

how do you determine working distance?

A
  • measure length from scope to eye

- 1/meters

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13
Q

once you stop seeing motion, are you done?

A
  • nope

- add a minus working distance

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14
Q

endpoint of retinoscopy

A

-when patient’s farpoint coincides with aperture of retinoscope

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15
Q

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

A

-MUST CORRECT FOR SPECIFIC WORKING DISTANCE

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16
Q

static retinoscopy

A
  • moving farpoint to the retinoscope

- use lenses

17
Q

direct retinoscopy

A
  • move retinoscope to far point of patients eye

- usually special circumstance/kids

18
Q

why is fundus reflex red/orange

A

–reflected from retina

19
Q

bracket

A
  • neutrality is a range of uncertainty between perceptible “with” and “against” motion
  • between absolute yes and absolute no
20
Q

six aspects of reflex

A
  1. brightness
  2. direction of motion
  3. speed of motion
  4. width
  5. definition
  6. alignment
21
Q

six aspects of reflex as you get closer to neutrality

A
  1. brighter
  2. motion decreases
  3. speed increases
  4. width narrows
  5. difinition increases
  6. becomes more aligned with streak
22
Q

speed increases when you get closer to neutrality???

A
  • yea.

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

23
Q

in general fundus reflex…

A

-gets easier to read as you get closer to neutrality

24
Q

abnormal fundus reflex

A
  • some portions may behave different than others
  • due to higher order aberrations
  • scissors motion
25
Q

What do you do when you have abnormal fundus reflex?

A
  • pay attention to the reflex in the center and ignore the rest
  • bracket, bracket, bracket
26
Q

should you allow accommodation in static retinoscopy?

A
  • no!

- should be relaxed

27
Q

fogging

A
  • 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
28
Q

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

A
  • pupils will get smaller

- all of a sudden change of motion without adding lenses

29
Q

potential problems with retinoscopy

A
  1. examiner too far to the side
  2. too many reflections
  3. accommodation
30
Q

what do you hope to get out of retinoscopy?

A

-consistent objective measurement

31
Q

results should be…

A

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

32
Q

consistant bias????

A
  • consistent hyperopic bias in young patients

- youll get a little more plus

Methods Block 3 (5 decks)

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