Visual Fields

Question 1

The entire area that can be seen when the eye is directed forward, including that which is seen with peripheral vision.
Or
The entire expanse of space visible at a given instant without moving the eyes.

Answer 1

Visual Field

Question 2

Visual Acuity

Answer 2

The ability to resolve something

Question 3

Visual Field Tests that are used:

Answer 3

1. Conformation
2. Tangent screen
3. Amsler Grid (wavy line?)
4. Automated Perimetry

Question 4

Visual Field Test

Answer 4

A test that measures the extend and distribution of the field of vision

Question 5

What are the diseases that can adversely affect the visual field?

Answer 5

• glaucoma
• strokes (CVA)
• tumor

Question 6

What medications can affect the visual field?

Answer 6

Hydroxychloroquine (Plaquenil) toxicity

Question 7

Why do we do VF testing?

Answer 7

• Many diseases can affect VF
• Medications can affect VF
• Occupational safety standards
• Determination of functional loss

Question 8

Give examples of occupational safety standards that are determined by VF’s

Answer 8

• Driver’s License qualification

- Pilots (private, commercial, military)

Question 9

Give reasonings for why we do vision field testing for the determination of functional loss:

Answer 9

• benefits for loss of VA

- insurance reimbursements (cosmetic vs. medically necessary)

Question 10

Name the different levels of Visual Field Testing

Answer 10

• Visual Field Screening
• Qualitative or Diagnostic Field Testing
• Quantitative Visual Field Testing

Question 11

Describe VF screening

Answer 11

• generally done when VF loss is unlikely but possible

- should be quick, easy and capable of eliciting a wide variety of defects

Question 12

Describe Qualitative or Diagnostic Field Testing

Answer 12

Designed to determine the characteristics of a VF defect (location, borders, size, shape, etc)

Examples: special DL testing, ptosis functional loss assessment, etc

Question 13

Describe Quantitative Visual Field Testing:

Answer 13

-Most sophisticated
Fully quantifies a known or suspended defect, so future changes detectable
Requires automated (full threshold) perimetry

Question 14

Incidence of VF loss is about ____

Answer 14

3-5%

over the age 65: 10-15%

Question 15

One study (n=1500) found ___ of those appearing for first optometric eye exam had VF defects and in half the cause was sight- or life-threatening

Answer 15

4.4% (1 in 20-25 people)

Question 16

VF defects are often _____ and may be the only detectable evidence of a disease/disorder

Answer 16

asymptomatic

Question 17

Should VF screening be done at all comprehensive eye exams?

Answer 17

Yes, with more extensive VF screening indicated whenever possible VF loss arises

Question 18

Describe Confrontation Visual Fields Tests.

Answer 18

• Can be done in multiple ways
• A quick, simple way to screen for gross VF loss
• Does not require special equipment and can easily be done with homebound or bedridden patients
• Sensitivity is not very high (better for posterior visual pathway lesions rather than anterior pathway lesions)

Question 19

Describe the technique for Confrontation VF’s

Answer 19

(counting fingers)

• Have them take off their glasses if they have them. Contacts are ok
• Examiner sits facing the patient (about 1 meter away)
• Patient covers 1 eye (test is done on each eye separately)
• Have patient look straight ahead into appropriate eye of the examiner
• Examiner introduces fingers (one, two or four) in each quadrant while making sure patient maintains fixation straight ahead (into their eye)

Question 20

True/False: A patient may come to you with no visual complaints, 20/20 VA, yet may have loss in VF.

Answer 20

True!

Question 21

True/False: Asymptomatic field loss may be the only detectable evidence of a serious medical condition.

Answer 21

True!

Question 22

True/False: Confrontation visual field examination, when done properly, can uncover otherwise undetectable pathology and potentially save a life.

Answer 22

True

Question 23

Common methods for assessing Central Visual Field?

Answer 23

• Amsler Grid testing

- specialized automated VF test strategies

Question 24

When should you test Central Visual Fields?

Answer 24

When macular disorders are suspected

Question 25

Unlike peripheral VF's, ____ is not routinely screened for.

Answer 25

Central VF's

Question 26

Describe Amsler Grid testing.

Answer 26

- Simple, quick way to check for defects within the central portion of the VF - Assesses roughly the central 10 degress of the VF - qualitative assessment of macular function

Question 27

What is the macula?

Answer 27

Portion of retina responsible for central vision

Question 28

This test should be: - done to detect gross abnormalities that may be caused by suspected disorders of the macula (e.g. AMD, etc) - may be given to patients with instructions on how to use themselves at home to monitor such conditions themselves

Answer 28

Amsler Grid Testing

Question 29

This defect within a field of vision is a distortion that can be found using an Amsler Grid testing.

Answer 29

Scotoma

Question 30

What is the normal response for an Amsler Grid Test?

Answer 30

- Dot at center is seen when looking directly at it - All four corners seen when looking at the dot - No areas of the grid are missing - No areas of the grid are distorted (no wavy lines)

Question 31

Abnormalities within Amsler Grid Testing may detect a defect at the _____. What can this indicate?

Answer 31

central VF | This may confirm macular dysfunction in someone suspected of macular disorder

Question 32

____ may be used to monitor change for those with known Central VF defects.

Answer 32

Amsler Grid

Question 33

Describe Normal Visual Fields

Answer 33

- Full in extent (up, down, left and right) in both eyes - Free of "blind spots" (within visual field) - Free of areas of distortion (within visual field)