Two-Color Dark-Adapted Perimetry Implemented With a Commercially Available Perimeter to Characterize Rod-Pathway...

To characterize rod-pathway function across the visual field using 2-color dark-adapted perimetry (2cDAP) implemented with conventional Octopus 900 Pro perimeters.

Eighteen visually normal individuals and two retinitis pigmentosa (RP) patients participated. Thresholds were measured under dark-adapted conditions at 15 locations along the horizontal meridian using short (450 nm) and long (610 nm) wavelength stimuli. Threshold differences between the two wavelengths were used to determine rod- vs cone-mediated function.

Among controls, peripheral and perifoveal thresholds for the short-wavelength stimulus were approximately 2 log units lower than for the long-wavelength stimulus. Foveal thresholds for the two wavelengths were similar. RP threshold profiles differed considerably from the controls, with normal foveal thresholds and high peripheral thresholds for both wavelengths.

2cDAP can be performed with an unmodified Octopus perimeter to evaluate rod function across the visual field and obtain information that is not available with standard automated perimetry. [.