DICOM PS3.17 2019b - Explanatory Information

DDD.2.3 Diffuse and Local Defect

DDD.2.3.1 Diffuse Defect

The Diffuse Defect is an estimate of the portion of a patient's visual field loss that is diffuse, or spread evenly across all portions of the visual field, in dB. In this graphical display, deviation from the average normal value for each test point is ranked on the x axis from 1 to 59, with 59 being the test point that has the greatest deviation from normal. Deviations from normal at each test point are represented on the y axis, in dB. The patient's actual test point deviations are represented by the thin blue line. Age corrected normal values are represented by the light blue band. The patient's deviation from normal at the test point ranked 25% among his or her own deviations is then estimated to be his or her diffuse visual field loss, represented by the dark blue band. This provides a graphical estimate of the remaining visual field loss for this patient, which is then presumed to consist of local visual field defects, which are more significant in management of glaucoma than diffuse defects.

Example of Diffuse Defect

Figure DDD.2-7. Example of Diffuse Defect


DICOM PS3.17 2019b - Explanatory Information