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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 some forms of objective refraction

A
  • retinoscopy
  • autorefraction
  • photorefraction
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3
Q

What does retinscopy rely on

A
  • eye is in a closed optical system (1 way in, 1 way out)
  • image detection occurs at outer limiting membrane
  • fundus reflex
  • reflecting surface for visible light is also at the outer limiting membrane
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4
Q

What gives us the objective refraction in retinoscopy

A
  • starting point for subjective refraction
  • independent objective confirmation of subjective results
  • good for patients unable or unwilling to give reliable subjective responses
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5
Q

Against motion in retinoscopy

A

Add minus

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6
Q

With motion in retinoscopy

A

Add plus

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7
Q

Retinoscopy set up

A
  • phoropter comfortably in front of patient
  • dark room
  • large fixation target at distance
  • arms length away, slightly temporal to eye being scoped
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8
Q

Retinoscopy technique

A
  1. Determine if spherical or astigmatic (reflex same in all meridians)
  2. Neutralize using plus for with, minute for against
  3. Do both eyes
  4. Add minus power to compensate for working distance
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9
Q

If the reflex is the same in all meridians

A

Its spherical

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10
Q

If the reflex is different in different meridians

A

Astigmatic, determine the two principal meridians

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11
Q

How to neutralize astigmatism in retinoscopy

A

Neutralize both principal meridians separately, leave “against” in second meridian scoped for minus cylinder

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12
Q

How do you compensate for working distance in retinoscopy

A

Add minus sphere (reciprocal of WD)

1/(WD in m)

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13
Q

endpoint of retinoscopy

A

Occurs when far point coincides with aperture of retinoscope

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14
Q

How to obtain far point of retinoscopy

A
  1. Moving far potion to retinoscope with lenses (static)

2. Moving retinoscope to far point (dynamic)

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15
Q

Static retinoscopy

A

Moving far point to retinoscope using lenses

-what we normally use

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16
Q

Dynamic retinoscopy

A

Moving retinoscope to far point

-special circumstances, kids who wont keep focus

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17
Q

Is everyone’s working distance the same?

A

No, varies from person to person, usually the arm length

18
Q

Fundus reflex color and reason

A

Red- organs because it is reflected from retina

19
Q

What is the procedure to obtain endpoint similar to?

A

Hand neutralization

20
Q

Neutrality

A

A range of uncertainty between perceptible “with” and “against” motions (bracket midway)

21
Q

Aspects of reflex indicate refractive status

A
  1. Brightness
  2. Direction of motion
  3. Speed of motion
  4. Width
  5. Definition
  6. Alignment
22
Q

When does the fundus reflex get brighter?

A

As you approach neutrality

23
Q

When doe the fundus reflex get dimmer?

A

When not close or when you have media opacities (cataract)

24
Q

When does the motion decrease?

A

As you approach neutrality (endpoint=no motion)

25
Q

When does speed of reflex increase?

A

As you approach neutrality

26
Q

What happens to the width when you approach neutrality?

A

Narrows

27
Q

When does definition increase in retinoscopy?

A

As you approach neutrality

28
Q

When does it become more aligned with streak in retinoscopy?

A

As you approach neutrality

29
Q

What causes abnormal fundus reflex?

A
  • higher order aberrations
  • some portions of reflex may behave different than others
  • scissors (peripheral portions of reflex differ from central portion)
30
Q

Accommodation in static retinoscopy

A

Should be relaxed

31
Q

How can you tell if someone is accommodating too much?

A

Look at reflex in center of pupil, pupils will also constrict

32
Q

Fogging

A

Adding more plus to both eyes prior to determine end point

33
Q

Where should patient fixate?

A

On distant target, not retinoscope light

34
Q

Potential problems

A
  • Examiner too far to side
  • reflections
  • accommodation
35
Q

Retinoscopy results

A

Should be repeatable within +/- .50D in each principal meridian and +/- 5 degrees axis of cylinder

36
Q

Is retinoscopy the same as a subjective refraction?

A

No

37
Q

Is retinoscopy the same thing as a the E.G. Rx?

A

No, wont necessarily use the same numbers, probably not going to write RX with this

38
Q

Is retinoscopy subjective or objective?

A

Objective

39
Q

What do retinoscopy findings require?

A

Modification during subjective refraction

40
Q

Retinoscopy findings and subjective findings

A

Highly correlated

41
Q

What retinoscopy in young patients

A

Consistent hyperopic bias

Methods BLOCK 3 (6 decks)

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