A perceptual experiment was conducted to measure the visibility of black-level differences in the proximity of a bright glare source. In a controlled viewing environment, visual difference thresholds were adaptively measured using dark, shadow-detail images shown on a high dynamic range liquid crystal display while an external LED lamp was used to induce intra-ocular glare over a small range of eccentricities. This high-contrast situation is relevant to high dynamic range displays that may have bright regions in displayed images, as well as to viewing environments that include lamps or other light sources. The resulting difference thresholds are modeled with a combination of the CIE total glare equation, the DICOM contrast visibility model, and a new estimate of adaptation luminance.