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OPTOMETRY AND VISION SCIENCE Copyright © 2012 American Academy of Optometry ORIGINAL ARTICLE Volume Perimetry: Measurement in Depth of
BibTeX
@MISC{Loss_optometryand,
author = {Visual Field Loss and Hini Satgunam and Henry L. Apfelbaum and Eli Peli},
title = {OPTOMETRY AND VISION SCIENCE Copyright © 2012 American Academy of Optometry ORIGINAL ARTICLE Volume Perimetry: Measurement in Depth of},
year = {}
}
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Abstract
Purpose. Volume scotomas are three-dimensional regions of space that are not visible to the observer. Volume perimetry maps volume scotomas. Volume scotomas predicted from combining monocular visual fields assume known fixation locus (mainly foveal). However, fixation loci are not always known, especially with central field loss (CFL). Here we demonstrate methods for measuring and calculating volume scotomas and discuss their practical implications. Methods. Three patients (bitemporal hemianopia, binasal scotoma, and CFL) were evaluated. Slices through the volume scotomas were measured at three distances: at the plane of fixation, at a plane anterior to fixation (representing anterior volume perimetry), and at a plane posterior to fixation (representing posterior volume perimetry). For anterior volume perimetry, patients fixated on a screen 100 cm away through a beamsplitter that reflected the perimetric stimulus (at 50 cm). For posterior volume perimetry, patients fixated on a near target (50 cm), while perimetric stimuli were presented on a screen 150 cm beyond fixation. At the plane of fixation, monocular visual fields under binocular viewing conditions were measured using a computerized dichoptic perimeter. Results. Posterior and anterior volume scotomas were documented in patients with bitemporal hemianopia and binasal scotomas, respectively. The CFL patient demonstrated both anterior and posterior volume scotomas. Scotoma magnitude was considered to determine its effect on visual function.
Keyphrases
volume scotoma vision science copyright optometry original article volume perimetry american academy posterior volume perimetry monocular visual field anterior volume perimetry binasal scotoma fixation locus perimetric stimulus bitemporal hemianopia plane posterior posterior volume scotoma central field loss plane anterior three-dimensional region volume perimetry map volume scotoma cfl patient near target anterior volume scotoma practical implication computerized dichoptic perimeter binocular viewing condition visual function scotoma magnitude
