MOTION PERIMETRY IDENTIFIES NERVE-FIBER BUNDLELIKE DEFECTS IN OCULAR HYPERTENSION

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 i dentify a coherent shift in position of 50% of dots in a defined circu lar 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 (millisec onds) 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 pa tients with OHT and 27 age-matched normal subjects. One eye was tested in each subject. Main Outcome Measures: Random dot motion stimuli siz e thresholds and total deviation probability plot data, reaction times , and spatial localization errors.Results: The patients with OHT had m ore abnormal test points in the to tal deviation probability plot anal ysis compared with the controls (P<.001, chi(2)). The abnormal test po ints were concentrated in the superior and inferior nasal regions. Six subjects had nerve fiber bundlelike defects to motion stimuli. Six su bjects (5 overlapping with the probability plot analysis) had abnormal glaucoma hemifield test results. The patients with OHT also had signi ficantly greater localization errors. Conclusion: Motion threshold per imetry may be a more sensitive method to detect visual field abnormali ties in OHT than conventional automated perimetry.