Hemi-Cloverleaf Pattern on Static Perimetry as an Indicator of Posterior Cortical Atrophy

Posterior cortical atrophy (PCA) is a rare, progressive, degenerative disease that initially manifests with visual dysfunction. Since its description over thirty years ago, debate remains over whether this is a variant of Alzheimer disease or a distinct entity, with pathology similar to Alzheimer's. Initially characterized by progressive impairment in many aspects of cortical visual function, in the early stages there is relative sparing of memory and executive function. Patients commonly present with non-descript visual complaints, often resulting in delayed diagnosis. On automated (Humphrey) visual field testing a majority demonstrate some degree of homonymous deficiency. The cloverleaf pattern on automated (Humphrey) visual fields is recognized as artifact of non-physiologic vision loss or visual inattention. This artifact results from the algorithm commonly used in static perimetry. We report a similar pattern where the affected field demonstrates a superimposed hemi-cloverleaf pattern from patients affected by PCA.