Module 3: HEENT Flashcards
What is the purpose of the confrontation test?
It is a gross measure of peripheral vision. It works by comparing the peripheral vision of the patient with that of the examiner by estimating the angle between the axis of the eye looking directly at the examiner and the peripheral axis where the object is first seen. (It assumes that the peripheral vision of the examiner is WNL.)
How do you perform the confrontation test?
- Stand 2 ft away at eye level with the patient.
- Pt covers one eye while the examiner covers their own opposite eye.
- Patient looks directly into the examiner’s eye while the examiner advances an object or finger from the periphery from a superior, inferior, nasal, and temporal direction.
- The patient indicates at which point the object or finger is seen.
Normal findings of the confrontation test?
The patient should see the finger/object of examiner at approx. the same time that it’s seen by examiner.
Approximates fields describe an angle of:
-50 degrees superiorly
-70 degrees inferiorly
-60 degrees nasally
-90 degrees temporally
What is a Tangent screen?
It provides a more precise measure of peripheral vision than the confrontation test. A patient is asked to stare at the center of a screen while the examiner maps the patient’s peripheral vision by noting the patient’s response to objects placed onto the screen.
What is the purpose of the cover test?
It detects phoria, a deviated alignment secondary to muscle weakness that may not be readily apparent on simple observation. This test works by disrupting the fusion reflex that normally keeps eyes parallel.
Example 1 of a cover test:
The patient is asked to gaze straight ahead. Both eyes gazed parallel until the examiner covers the left eye. When the left eye is covered, the right eye drifts medially. When the cover was removed, the right eye jerked back into parallel position. Why?
The right eye is weaker. The fusion reflex was disrupted.
Example 2 of a cover test:
A patient was asked to gaze straight ahead. Both eyes gazed parallel until the examiner covered the left eye. When the left eye was covered, the right eye continued to gaze straight ahead. When the cover was removed, the left eye jerked back into parallel position. Why? The left eye is weaker.
So what does the cover test do?
It detects small degrees of deviated alignment by interrupting the fusion reflex that maintains eyes in parallel alignment. During the test, the eye with weak muscles will drift when an eye is covered and will jerk back into alignment when uncovered.
What is it called when a weakness in eye muscles that occurs only when the fusion reflex is blocked?
A phoria (ex. strabismus and tropia are terms that referred to a constant misalignment of the eyes. Esotropia = turn inward. Exotropia = turn outward.
What is another name for the corneal light reflex test?
Hirscherg Test
What is the purpose of the corneal light reflex test?
It is used to detect strabismus. Especially important in children.
How do you perform the corneal light reflex test?
The examiner shines a light toward the patient’s eyes and observes the spot on the cornea where the light is reflected.
What is considered a normal finding for the corneal light reflex test?
In a patient with normal alignment, the light will be reflected at the same place on both corneas or very slightly medially on both pupils. If it is reflected at different places, this will indicate strabismus.
What does the Snellen chart measure?
Distance vision.
What is the procedure for testing visual acuity using the Snellen chart?
- Stand 20 ft away from chart. Should be eye level and a well lighted area.
- PRESCRIPTION Glasses/contacts should be worn. NOT READING GLASSES.
- Testing should occur with right eye covered, left eye covered , then both uncovered.
- The patient should read the smallest line possible without hesitancy, squinting, or leaning forward.
What is visual acuity in a child?
Visual acuity is usually less. A reading of 20/50 may be normal for a child of 3; 20/40 may be normal for child of 4; 20/30 may be normal for a child of 5. The upper limits of normal vary +/- 10 feet among different sources.
When is it important to test near vision?
In adults >40 years.
How do you test near vision?
A Rosenbaum chart is used. With one eye covered, the patient reads the smaller line of letters on a card held approximately 14 inches from the eye. Can also use a Jaeger Near Point Card.
What is normal near vision?
14/14
What does a near vision test screen for?
Presbyopia, a decrease in accommodation that occurs with aging.
What does the diagnostic positions test measure?
It is used to identify extraocular muscle dysfunction that may result from paralysis or cranial nerve dysfunction. It is used to identify nystagmus that may occur with certain conditions such as disease invoking the semicircular canals, multiple sclerosis, etc.
How do you conduct a positions test?
Examiner has the patient follow an object (held at a distance of +/- 12 inches) with the eyes while keeping the head still. The object is moved through the 6 cardinal fields of gaze while the patient tracks movement of the object with the eyes.
Diagnostic Positions Test interpretation:
Eye movements are coordinated by cranial nerves III, IV, VI and by the extra ocular muscles. A normal response is parallel tracking of all movements.
What does Nystagmus indicate?
May indicate an inner ear or neurological problem. May also indicate inebriation. Mild nystagmus at extreme lateral gaze is a normal finding. See chart on slide 44 to determine which muscle/cranial nerve is not functioning properly.
What is another name for the diagnostic positions test?
The test of extra ocular movement or EOMS.
What does the accommodation test measure?
Pupillary constriction and convergence of the aces of the eyes that normally occurs when eyes adjust for near vision.
How do you perform an accommodation test?
Have the patient focus on a distant object (this causes the pupils to dilate), then ask the patient to shift the gaze to the examiner’s finger which is held about 3 in from the patient’s nose. A normal response is constriction of the pupils and convergence of the eye’s axes.
How to interpret an accommodation test:
An absence of either constriction or convergence or an asymmetric response is abnormal. (Ex. CN III damage will result in pupil dilation and lateral deviation of the eye.)
What is the purpose of the Ishihara Test?
Tests color vision
How do you perform the Ishihara test?
With one eye covered, the patient is asked to identify numbers or objects on a slide within a time frame of +/- 3 seconds. Patients who have various types of color vision will not be able to identify colored numbers or objects within patterns of dots.
What is the purpose of the Amsler Grid?
Used to test for defects in the central visual field. Such defects are typical of macular degeneration.
How do you test central vision with the Amsler Grid?
The Amsler grid is held at +/- 14 inches away. (Reading glasses may be worn.) With one eye covered, the patient stares at the central dot on the grid. Repeat with the other eye.
What are some abnormalities with the Amsler Grid?
Abnormalities indicated by wavy, crooked, or bent lines. Variances in box shape or size. Missing or discolored lines.
Patient reports that he is beginning to have difficulty seeing road signs until he gets close to them. What test would you use?
A test of visual acuity using the Snellen chart will determine if distance vision is a problem.
You notice that your patient didn’t flinch as an object fell within inches of his left temple. It was only after it crashed that it caught your patient’s attention. You suspect a deficit in his peripheral vision. How would you test his visual fields?
In order to screen for approximate peripheral vision, you would use the confrontation test. For more accurate testing, a tangent screen would be used.
A mother states “I think my son has lazy eye.” How would you test for this?
The cover test is designed to detect “lazy eye” by disrupting the fusion reflex.
What are the tests of Visual Acuity?
Snellen Chart = Distance vision
Rosenbaum or Jaeger Cards = Near vision
What helps tests peripheral vision?
Confrontation test and Tangent screen
What helps tests Central vision?
Amsler grid
What are tests of EOM function?
Corneal light reflex (Hirshberg test), cover test, diagnostic positions test.
