Entrance test Flashcards

1
Q

Hirschberg test

A
  • objective estimate and measurement of a deviation/strabimus
  • evaluate the visual axes OU under binocular conditions at near
  • useful in young/difficult patients
  • WITHOUT GLASSES
  • penlight held 50cm and patient fixates on it with both eyes
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2
Q

3 possible corneal reflex positions

A
  1. center of pupil
  2. nasal to the pupil
  3. temporal to the pupil
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3
Q

Positive angle lambda/kappa

A
  • exo posture
  • eye naturally sits out, reflex brings it in
  • nasal to the pupil reflex
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4
Q

Negative angle lambda/kappa

A
  • eso posture
  • eye natually sits it, reflex brings it out
  • temporal to the pupil reflex
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5
Q

Absence of strabismus

A
  • if the reflex are in the same relative position compared to when the eyes are occluded
  • corneal reflex should be centered in both eyes
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6
Q

Presence of strabismus

A
  • reflexes are not in the same relative position

- totally different angle monocularly and binocularly

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7
Q

deviation and prism diopters

A

For 1mm of estimated deviation, it is approximately a deviation of 22 prism diopters

-FUR SURE ON BLOCK

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8
Q

Recording of Hirschberg

A
  • indicate you used hirschberg
  • no strabismus=ortho/symmetrical
  • yes strabismus=record deviated eye, size and direction of the deviation

44pd LET

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9
Q

Krimsky Test

A
  • use prisms to determine the angle of deviation seen on Hirschberg
  • prisms are placed in front of the FIXATING eye until the corneal reflexes are symmetrical
  • prism reflection test
  • not super accurate
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10
Q

Base prism correction

A

esotropia=BO

exotropia=BI

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11
Q

Near point convergence

A
  • determine the ability to converge and maintain fusion
  • both eyes come in to one point
  • WITH CORRECTION, good lighting, 40cm
  • transilluminator is used for initial screening and if there is receeding, use red glass and then accommodative target
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12
Q

Basic Krimsky method

A
  • patient look at light
  • ask if they see double, if yes, more target back
  • move target towards patient until they hit break point
  • move the target until they hit recovery point
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13
Q

Break point

A

-patient first reports double vision or one eye loses fixation

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14
Q

Recovery point

A

-patient first regains single vision or where you notice fixation of both eyes

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15
Q

Normal NPC reading

A
  • measure with ruler at bridge of nose or at glasses
  • Break: 2.5cm
  • recovery: 5cm(TTN)
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16
Q

Abnormal NPC

A
  • repeat procedure with red/green glasses
  • red is always for OD
  • differentiate what each eye is doing
  • result is more receding

if still abnormal,
-repeat procedure with accomodative target

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17
Q

Convergence and accommodation

A

VERY CLOSELY RELATED TO EACH OTHER
convergence-focus it
accommodation-keep it clear

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18
Q

Convergence insufficiency

A
  • if a patient has convergence insufficiency and you keep repeating procedures, you’re gonna get a ton of different readings because of fatigue
  • fatigue=more receding
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19
Q

Recording NPC

A
  • with or without correction
  • the target used
  • break distance cm/ recovery distance cm
  • deviated eye and direction
  • diplopia or suppression
  • light, red/green, accommodative
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20
Q

diplopia/ supression

A
  • diplopia:double vision

- suppression: eye move

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21
Q

Receded NPC can cause…

A
  • binocular vision problems
  • eyestrain/asthenopia
  • reading problems
  • difficulty with near point tasks
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22
Q

Amplitude of Accommodation

A
  • measures a patient;s ability to accommodate
  • WITH GLASSES
  • monocular
  • in diopters
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23
Q

Push-up method

A
  • method of amplitude of accommodation
  • tell patient to keep letter CLEAR
  • slowly move letters closer to the patient until they report blur
24
Q

Measure amplitude

A
  • measure the distance from the patient’s spectacle plane in cm
  • this is near point of accommodation
25
Convert near point of accommodation
- cm to diopters | - 100/NPA
26
What size is target?
20/30ish | -too big doesn't let patient use their full accommodative ability
27
Pull Away method
- method of amplitude of accommodation - hold letter painfully close to patient(0.5cm) until they see blur - slowly move target out until they can TELL YOU the letter
28
Record amplitude of accommodation
- method used | - amplitude of accommodation in Diopters
29
Normal amplitude of accommodation
- both eyes should be within 1D of each other | - accommodation decreases with age, can be affected by meds and disease
30
Hofstetter's formula
minimum expected amplitude= 15-0.25(age of patient)
31
Donder's table
-table for age and amplitude
32
What affects accommodation?
- decreases with age - alcohol - meds(CNS stimulants, cyclo) - trauma to iris - iridocyclitis - diabetes/MS
33
Binocular vision
- allows us to appreciate many ASPECTS of a target - minute details - fuse image
34
Sensory system and binocular image
- fusion - constructs single perception from two retinal images - gives the distance of the target - brain
35
Motor system and binocular vision
- vergences and eye movements - muscles - coordinates the orientation of the eyes in all distances and on your moving targets - coordinates with accommodative system to maintain clear image - depth and focus
36
Poor binocular vision can lead to...
- fatigue - eye strain - headaches
37
Binocular vision is in jeopardy with...
- eye disease: takes one eye out of commission - strabismus: no way you can have binocular vision - trauma: eye can not function due to trauma
38
When binocular vision works well...
- one image from both retinal images - high resolution - little disparity
39
Disparity
- eyes bounce back and forth because trouble with fusion | - sees double/blur
40
Binocular vision advantage
- depth - more precise - quicker
41
Stereopsis
- measure fine depth perception by evaluating the ability to fuse stereoscopic targets - wear corrective lenses over Polaroid glasses - overhead light - 40cm
42
basic steps for stereopsis
1. start with middle box(most difficult) and keep going until patient misses 2 in a row 2. if they can't do that row, go to the bottom row 3. if can't see those, go to top row
43
Record Stereo
- at N and what test used - indicate with or without correction - recorded in seconds of arc
44
Expected stereo
at near:20-30 seconds of arc if really high, oh no do cover test
45
Worth 4 Dot
- assess flat fusion at N(40cm) and D - ability to detect a small central scotoma - do when stereo is below normal - WITH CORRECTION - red lens=OD
46
3 degrees of fusion
1. simultaneous perception and superimposition(NPC break) 2. Flat fusion(2 images into 1, but no depth) 3. Stereopsis(binocularity is excecllent)
47
Why is worth 4 dot done with correction?
- you want best possible vision | - do it with habitual and if you think you should do it again after refraction, do it again
48
What do the dots look like?
- red on top - white on bottom - green to the side
49
What does it mean based on the number of dots the patient sees?
4 dots: normal flat fusion 2 dots: only OD being used, OS suppressed 3 dots: only OS being used, OD suppressed 5 dots: diplopia(ONLY 5 DOTS NO MORE)
50
Uncrossed diplopia
- eso deviation | - red dots all on right and green dots all on left
51
Crossed diplopia
- exo deviation | - red dots all on left and green dots all on right
52
worth 4 dot hyper deviation
- vertical diplopia - red dots on bottom, green dots on top=right hyper - red dots on top and green on bottom=left hyper
53
Testing for scotoma at Near
- make sure there is normal worth 4 dot test at near - have patient tell you if there is a change in what they see - move flashlight AWAY - STOP when patient says there is a change in the number of dots of at 10 feet.
54
Analyze W4D at near
- if it changes to see 2 dots, OD is working, OS is suppressed, cover OD, if dots come back, scotoma is only there with fusion. - if the dots do not come back, the scotoma is unilateral
55
Recording W4D
-record the distance Fusion at distance and near fusion at distance, suppression OD at near diplopia, eso with right hyper at N