### Practical Exam Questions: Visual Field Testing
**1. Definitions & Purposes**
- Define "visual field" and explain why perimetry is always performed monocularly.
- List three indications for performing perimetry based on patient history.
**2. Factors Influencing Testing**
- How does a pupil diameter smaller than 3 mm affect visual field results? What must be
documented?
- Explain the difference between a "strict criterion" and "relaxed criterion" in patient responses.
**3. Testing Methods**
- Describe the procedure for administering the Amsler Grid test. What patient population is it
most suited for?
- Compare manual perimetry (e.g., Goldmann Bowl) and automated perimetry (e.g., Humphrey
Field Analyzer) in terms of advantages and limitations.
**4. Equipment & Setup**
- A patient has a distance prescription of -2.50 -1.00 x 090 and is an absolute presbyope.
Calculate the trial lens power needed for perimetry.
- What steps would you take if a patient’s fixation target appears blurry during setup?
**5. Test Patterns**
- When would you select the Central 10-2 test pattern? Provide two clinical examples.
- Explain the difference between the Humphrey 30-2 and 24-2 test patterns.
**6. Reliability & Interpretation**
- During testing, a patient has 4 fixation losses out of 12 presentations. Is this acceptable? How
would you address this?
- Interpret a decibel graph result of 15 dB in the central field. What does this indicate about the
patient’s vision?
**7. Documentation & Coding**
- A patient undergoes a Humphrey 24-2 threshold test. What CPT code would you use for
billing? What documentation is required?
- Document the following reliability indices: Fixation Losses: 2/10, False Positives: 5%, False
Negatives: 12%.
**8. Troubleshooting & Responsibilities**
- A test result shows a generalized depression in the central 30°. Identify two possible causes
and how to prevent them.
- List three responsibilities of a technician during visual field testing to ensure accurate results.
**9. Scenario-Based Application**
- A patient with ptosis (drooping eyelid) is undergoing testing. How might this affect the results,
and what adjustments would you make?
- During testing, a patient becomes fatigued and starts missing stimuli. What actions would you
take to improve reliability?
**10. Critical Thinking**
- A patient’s visual field printout shows a ring scotoma. What equipment error could explain this,
and how would you correct it?
- Why is it critical to remove contact lenses before perimetry? What artifact might occur if they
are left in?
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**Scoring Focus**:
- Accuracy in calculations (e.g., trial lenses).
- Understanding of test patterns and their clinical applications.
- Ability to troubleshoot common errors (e.g., fixation losses, artifacts).
- Proper documentation and coding practices.
- Patient communication and procedural adherence.
