The Foresee PHP is a non-invasive, easy-to-perform eye exam that has been proven to be highly effective in identifying elevations in the retinal pigment epithelium (RPE) consistent with conversion from an intermediate to an advanced stage, or “wet” AMD. Its diagnostic capability is based on hyperacuity, the inherent human ability to visually detect the misalignment of objects relative to other objects in space. Hyperacuity is 10 times more sensitive than standard visual acuity and is characteristically stable regardless of a patient’s age or physical condition.
Preferential hyperacuity perimetry uses a form of perimetry that is similar to visual field testing, but instead of using white-on-white stimuli, it uses Vernier hyperacuity —the ability to perceive minute differences in the relative spatial localization of two objects in space.
The Foresee PHP maps defects within a patient’s visual field by analyzing responses to “dot deviation signals” flashing on a screen. A signal, consisting of a series of closely spaced dots in a single straight line with one or more dots out of alignment, is displayed on the screen for 160 milliseconds. The patient uses a stylus pen to touch the screen to identify the most prominent distortion in the line.
A typical 3-to-5 minute test measures 500 retinal data points covering the central 14° of the macular visual field. The response patterns are recorded, analyzed and compared to the normative database, producing a report revealing the relative location of the defects in the macular area.