Figure 1.

Evaluating macular rod function using the mHFA and MP-1S. (A) Spectral distribution of the monochromatic blue and red colored stimuli used with the mHFA (left) and the broadband blue stimulus used with the MP-1S (right), superimposed over the human scotopic and photopic luminosity functions (thin gray curves). (B) Effective sensitivities obtained with the MP-1S by extending the limited dynamic range of the blue colored stimuli with the use of a range of ND filters. Each log unit of ND filter (+1 to +4 ND) shifts the instrument dynamic range to lower luminances by 10 dB. (C) A total of 18 locations were sampled at 2° intervals, between 6° and 14° eccentricity from the fovea along the horizontal and vertical meridia. The mean effective thresholds for the MP-1S in controls did not vary substantially across the test locations.