Description | Stimulus (photons/s/μm2) | Background (photons/s/μm2) | Michaelson or Weber contrast | Opsin | Stimulusa | ||
---|---|---|---|---|---|---|---|
R*/rod/s | R*/M-cones/s | R*/S-cone/s | |||||
Dim visible stimulation (OLED) | 2.7 × 104 | 1.8 × 102b | Weber = 269% | Rod | 8.1 × 104 | 5.6 × 103 | — |
Bright visible stimulation (OLED) | 9.7 × 105 | 6.3 × 104 | Weber = 96% | M-opsin and rod | 3.1 × 105 | 2.0 × 104 | — |
6.3 × 104 | 1.2 × 105 | Weber = −11% | |||||
6.3 × 104 | 7.2 × 105 | Weber = −71% | |||||
Bright UV stimulation (375 nm LED) | 5.1 × 105 | ∼0 | Michaelson contrast = 100% | S-opsin, M-opsin, and rod | 7.0 × 104 | 5.5 × 103 | 4.5 × 105 |
Green stimulation (535 nm) | 6.4 × 105 | ∼0 | Michaelson contrast = 100% | M-opsin and rod | 3.5 × 105 | 2.6 × 104 | — |
Light stimuli were generated with either a broadband OLED or a 375 nm or 535 nm LED masked by a digital mirror device (Figure 1C). Photon flux was estimated as the average intensity measured with a power meter placed at the focal plane. Intensity values were converted to photoisomerizations per rod and assumed a rod cross-section of 0.85 μm2 and a cone cross-section of 1 μm2.
↵aAssuming 5% M-opsin in ventral retina where recordings were done as per Wang et al. (2011).
↵bBelow sensitivity of power meter. For OLED, we estimated by assuming 27% transmission through neutral density filter.