Entrance Tests Flashcards
Examples of a few more entrance tests..
Hirschberg and Krimsky
Near Point of Convergence
Accommodative Amplitude
Stereopsis
Worth 4 Dot
What is the Hirschberg test?
A penlight is held straight in front of a patients face at about 50 cm. the patient is instructed to fixate on the penlight with both eyes open. Occlude one eye at a time to observe the corneal reflex.
Rough objective and measurement of a deviation/strabismus. Evaluating the visual axes OU under binocular conditions at near.
Hirschberg test is useful in what type of patients?
Young and uncooperative
Should the Hirschberg test be done with or without glasses?
Without
3 possible corneal reflex positions
Center of the pupil
Nasal to the pupil
Temporal to the pupil
What is a strabismus?
When there is different corneal reflexes in the two eyes
In the absence of the strabismus, the corneal reflex should be…
Centered in both eyes
recording of Hirschberg test example
Hirschberg: no strabismus or ortho
Hirschberg: 44pd LET; Krimsky 45pd LET
What is the Krimsky test?
Use prisms to determine the angle of deviation seen on the Hirshberg test.
In Krimsky, prisms are placed in front of the ___________ ____ until the corneal reflexes are symmetrical.
Fixating eye
Base out prism is used for _______
Esotropia
Base in prism is used for ________
Exotropia
What is NPC?
Near Point of convergence
What is the point of NPC?
To determine the ability to converge and maintain fusion.
Conditions for NPC
Done with correction
Good lighting
And star at at about 40 cm
What objects are/can be used for NPC?
A penlight/transilluminator, red glass, and a near accommodative target
NPC Prodecure
Instruct pt to look at the light
Ask pt to tell if it’s single of double, if double move object away
Move object towards pt while paying attention to pt eyes
record break point and recovery
What is the break point of NPC?
The distance at which the pt sees double or you see an eye lose fixation
What is the recovery point in NPC?
The distance at which the double vision becomes single vision, either by pt discretion or where you notice fixation
Normal NPC finding
Break 2.5cm/Recovery 5cm
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
When should the NPC be repeated numerous times? Why?
When the pt has convergence insufficiency problems.
Because there will be changes in the NPC each time because of fatigue!
NPC recording example
NPC sc light: 10cm/15cm, OD out, suppression
Red/Green: 15cm/20cm, OD out, suppression
Accommodative: 12cm/16cm, OD out suppression
What is Amplitude of Accomodation?
Measures a pt’s ability to accommodate (in diopters)
Conditions of Amplitude of Accomodation
Pt wears correction,
Near point accommodative target,
Occluder,
Illumination
Push up Method of Accomodation
Tell pt to occlude one eye,
Tell pt to look at a row of letters,
Tell pt to keep the letters clear,
Slowly most the letters closer to pt until pt reports blur
Measure the distance
Pull away method of Accomodation
Occlude one eye, tell pt to look at row of letters
Tell pt to keep letters clear
Hold letters/target very close to the pt open eye, about 0.5cm
Pt should report blur, so tell pt to say when pt reports clarity.
Measure distance in cm
Recording Accomodation
method use (Push up or pull away) Amplitude of Accomodation for each eye (D)
Ex. Amp of Accomodation: 9D OD, 10D OS
Why measure Accomodation?
It decreases with age.
Affected by medications.
Trauma causing iris tear (damage)
Alcohol
Glaucoma can affect it
Diabetes, multiple sclerosis
