Entrance Tests Flashcards
What is the Hirschberg Test?
This is a rough objective estimate and measurement of a deviation/strabismus. Evaluating the visual axes OU under binocular conditions at near.
The Hirschberg test is especially useful for patients who are:
young and uncooperative
Should the Hirschberg test be done with glasses or without?
WITHOUT glasses
1st step of the Hirschberg test: A penlight is held straight in front of a patient’s face at about ____. The patient is instructed to fixate on the penlight with ____.
50 cm
both eyes open
2nd step of the Hirschberg test:
Occlude one eye at a time to observe the position of the corneal reflex.
3 possible corneal reflex positions:
Center of the pupil
Nasal to the pupil (positive angle lambda or kappa, exo posture)
Temporal to the pupil (negative angle lambda or kappa, eso posture)
In the Hirschberg test, what are the 3 possible corneal reflex positions?
3 possible corneal reflex positions: Center of the pupil Nasal to the pupil (positive angle lambda or kappa, exo posture) Temporal to the pupil (negative angle lambda or kappa, eso posture)
3rd step of the Hirschberg test:
Then occlude the other eye.
Now look at the corneal reflex in each eye.
The Hirschberg test indicates whether or not there is strabismus. How?
Now look at the corneal reflex in each eye. If the reflex are in the same relative position, compared to when the eyes occluded, there is no strabismus If the reflexes are not in the same relative position, there is strabismus. Determine the direction relative to angle lambda.
Hirschberg test: In the absence of strabismus, the corneal reflex should be _____ in both eyes.
centered
Hirschberg test: In the presence of strabismus, the reflex will not be in the center of the ______ eye and it will be different from the relative angle lambda in that eye.
deviated
Hirschberg test: For 1 mm of estimated deviation, it is approximately a deviation of _____ prism diopters
22
How do you record results of a Hirschberg test?
In recording, indicate that you did Hirschberg.
NO strabismus: record ortho or symmetrical
Strabismus present: record the deviated eye, the size and direction of the deviation.
Hirschberg: no strabismus or ortho
Hirschberg: 44pd LET; Krimsky 45pd LE
What is the Krimsky test?
Krimsky test: use prisms to determine the angle of deviation seen on Hirschberg test.
Krimsky:Prisms are placed in front of the ______ until the corneal reflexes are symmetrical.
fixating eye
Base Out prism is used for 1. _______
Base In prism is used for 2. _______
- esotropia
2. exotropia
In the Prism Reflection Test, the prism is held in front of the _______ until the corneal reflex is symmetrical.
deviated eye
What is the Near point of Convergence (NPC)?
This is to determine the ability to converge and maintain fusion.
NPC is done _______, good lighting and start at about _______.
with correction
40cm
NPC: Requires a penlight or transilluminator, red glass, near accommodative target (_____ letter).
a 20/30
Note: the transilluminator is used for the initial screening and if there is a receeded NPC, the red glass and then the accommodative target is used.
What are the first steps of the NPC?
- Instruct the patient to look at the light
- Ask the patient if it is single or double; if double, move the target away further back
- Move the target towards the patient while paying attention to the eyes.
NPC: Move it into the patient until the patient reports double or you see one eye loses fixation, take note of this distance (_________).
Now move the target back again until the patient reports single vision or where you notice refixation. Measure this distance (_______)
- break point
2. recovery
What is a normal finding of NPC?
Normal finding: Break 2.5cm/Recovery 5cm, or, to the nose (TTN) This should be the same with penlight, red glass and with an accommodative target!
If the NPC is abnormal:
Repeat with red glass over right eye (or Red Green glasses); then repeat a 3rd time with an accommodative target.
How do you record NPC results?
Record
• with or without correction
• the target used
• the distance (cm) where there was a break or diplopia (from bridge of nose or spectacle plane)
• distance of recovery
• the deviated eye and the direction
• diplopia or suppression (break without diplopia)
Example
• NPC cc light: TTN
• NPC sc light: 10cm/15cm, OD out, suppression
Red/Green: 15cm/20cm, OD out, suppression Accommodative: 12cm/16cm, OD out, suppression
Receeded NPC can cause
- Binocular vision problems
- Eyestrain/asthenopia
- Reading difficulties
- Difficulties with near point tasks
What is the Amplitude of Accommodation?
Measures a patient ability to accommodate (in diopters)
What do you need for the Amplitude of Accommodation test? Does the patient do it with or without correction?
Patient wears correction, near point accommodative target, occluder, illumination
Near Point Accommodation Push Up Method: Tell the patient to occlude one eye, tell patient to look at a row of letters (one or 2 lines better than BCVA at N)
Tell the patient to keep the letters clear. Slowly move the letters _______ to the patient, until the patient reports blur.
Measure the distance from the patient’s spectacle plane in _____. This is the near point of accommodation
To convert into diopter, divide 100 by the near point of accommodation and report the amplitude of accommodation in D
Occlude the other eye and repeat.
cm
closer