Question 6: What are false negatives and what are features on a visual field which suggest the defect is caused by false negatives?

Question 6: What are false negatives and what are features on a visual field which suggest the defect is caused by false negatives?

False negatives.

False negatives are recorded when the patient does not respond to a stimulus of higher intensity presented at the same location where previously the patient has responded to a lower intensity stimulus. False negatives of more than 33% suggest poor reliability of the fields.  False-negative do not necessarily indicate unreliable fields. Areas of depressed sensitivity, and a brighter stimulus may truly not be visible on second presentation  in areas of visual field damage. Visual fields with false-negative responses should be interpreted light of the entire clinical picture.

One characteristic field defect seen in people with high false-negative rates related to fatigue is the “cloverleaf” field in which the patient responds to the early test points but then fails to respond to subsequent stimuli. A variant of this field is the apparently constricted field, a “pseudocentral island,” in which the patient failed to respond to the points tested last which were, because of the test logic, the peripheral points.