ACAM — a novel Adaptive CAMpimetry technique for a fast, precise, and reliable measurement of visual field defect borders
Mon—Casino_1.801—Poster1—2014
Presented by: Doris Schmid
ACAM is a novel campimetry designed to improve the measurement of visual field defects (VFDs) following brain injury. Precise and efficient assessment of VFDs is essential for diagnostic purposes and to evaluate therapeutic progress (specifically for restitutive approaches). Traditional perimetry and campimetry, however, use targets presented at constant spatial intervals across the visual field, resulting both in low efficiency and low precision. ACAM improves upon this by using an adaptive procedure to increase density of target presentations near the presumed VFD-border while reducing density far from the border. Feasibility and reliability of ACAM were assessed in two experiments with healthy participants, using the natural blind spot (NBS) as a model VFD. In both experiments, ACAM was applied repeatedly to the same eye of each participant. In experiment 1 (N=22), two versions of ACAM were tested: (1) all targets within the NBS were activated, (2) only those targets at the NBS-border were activated. This modification resulted in a significantly reduced test duration. In experiment 2, we applied the border-zone version twice in 31 participants, and a third time in 15 participants. Due to the adaptive procedure, target positions differ across repetitions. Nonetheless, in both experiments, resulting NBS-centres, as well as NBS-width and -height, did not differ significantly between repetitions. Additionally, Bayes factors provided anecdotal to moderate evidence supporting the consistency of NBS-values within participants. In conclusion, ACAM provides a reliable method for measuring the NBS. Through its adaptive procedure, ACAM achieves high precision in delineating VFD-borders while keeping testing time minimal.
Keywords: Visual field defect, border zone, campimetry, perimetry, adaptive procedure, natural blind spot, hemianopia