Red flags and artifacts in perimetry

ABSTRACT

Background: As perimetry is a psychophysical test, the thresholds obtained are not only dependent on the functional architecture of the visual system but also on a variety of physical and cognitive factors. Factors such as, Lens rim artifact, improper refraction, miosed pupil and blepharoptosis, can affect luminance thresholds. Additionally, cognitive factors such as patient's attention, motivation, fatigue, and response bias can influence the obtained thresholds. Purpose: The video describes identification of various artifacts in Humphrey visual field printout and it has some useful teaching points to recognize and learn. Synopsis Visual field test is critical for assessment and to document progression of glaucoma, but is prone to errors and artifacts. Fortunately, the patterns of such artifactual field loss are often characteristic and easily recognizable. Highlights Several types of errors canlead to inaccurate results. Proper instructions and patient supervision during the test helps to improve the test results. The technician should ensure correct patient’s data entry. Careful examination of the obtained data on the printout is essential to detect any errors that can lead to misinterpretation of visual field, false alarms, and wrong clinical conclusion.