Confrontation visual field loss as a function of decibel sensitivity loss on automated static perimetry. Implications on the accuracy of confrontation visual field testing

Abstract

Purpose: To evaluate the accuracy of confrontation visual field testing with regard to the density of the visual field defect and its location in the peripheral visual field.

Methods: A prospective comparison of confrontation visual field testing with full-threshold Humphrey automated static perimetry C24-2 or C30-2 was conducted at a university eye center over a 3-month period. Seventy-two patients with a variety of neurologic and ophthalmologic conditions underwent confrontation visual field testing and automated perimetry as a part of their evaluation. One visual field from each patient was analyzed for this study.

Results: Confrontation visual field testing yielded an overall sensitivity for detecting an abnormal visual field (full-field analysis) of 63%, when sensitivity of confrontation testing rested on the detection of just one abnormal quadrant. The sensitivity of confrontation testing varied depending on the type of visual field loss present: 51% for arcuate scotomas, 67% for visual field constriction, 78% for altitudinal scotomas, and 90% for hemianopias. The sensitivity of detecting abnormal visual field quadrants, rather than the full-field analysis, was, however, poor at 38%. The sensitivity of confrontation testing was lower for superior quadrant defects and higher for inferior quadrant defects. The estimated probability of detecting an abnormal visual field quadrant occurring at a -26-decibel sensitivity loss from age-matched healthy patients for superior quadrant defects and a -19-decibel sensitivity loss for inferior quadrant defects was 50%. The increased sensitivity noted for visual field defects and for inferior quadrant defects appears to be related, in part, to the density of the visual field loss present.

Conclusion: Confrontation visual field testing is relatively insensitive unless a moderate to dense defect is present, and as such is a poor screening test. However, when visual field defects are identified with confrontation visual field testing, the defects often are real as per the high specificity (97%) and high positive predictive value (96%).