Motion perimetry identifies nerve fiber bundlelike defects in ocular hypertension
M. Wall, C. S. Jennisch and P. M. Munden
Department of Neurology, College of Medicine, University of Iowa, Iowa City, USA.
OBJECTIVE: To determine whether patients with ocular hypertension (OHT)
have elevated motion perimetry thresholds. DESIGN: Motion perimetry uses a
customized computer graphics program to detect the ability to identify a
coherent shift in position of 50% of dots in a defined circular area
against a background of fixed dots. Motion size threshold is defined as the
smallest circular area in which dot motion is detected. Subjects respond by
touching the area of the computer monitor with a light pen where motion
stimuli are perceived. Reaction times (milliseconds) to stimuli and
localization error (number of pixels from target center) are also obtained
for each trial. SETTING: University hospital ophthalmology clinic. PATIENTS
OR OTHER PARTICIPANTS: Twenty-seven patients with OHT and 27 age-matched
normal subjects. One eye was tested in each subject. MAIN OUTCOME MEASURES:
Random dot motion stimuli size thresholds and total deviation probability
plot data, reaction times, and spatial localization errors. RESULTS: The
patients with OHT had more abnormal test points in the total deviation
probability plot analysis compared with the controls (P < .001, chi 2).
The abnormal test points were concentrated in the superior and inferior
nasal regions. Six subjects had nerve fiber bundlelike defects to motion
stimuli. Six subjects (5 overlapping with the probability plot analysis)
had abnormal glaucoma hemifield test results. The patients with OHT also
had significantly greater localization errors. CONCLUSION: Motion threshold
perimetry may be a more sensitive method to detect visual field
abnormalities in OHT than conventional automated perimetry.
