The spectral sensitivity of blue-sensitive pigeon cones: evidence for complete screening of the visual pigment by the oil-droplets.

The relative spectral sensitivity of blue-sensitive pigeon cones was determined using flicker-photometry based on mass ERG-responses from intact subjects during high-level light adaptation. The resulting spectral sensitivity curve can be mimicked by a P460 nomogram screened by an oil-droplet that absorbs 50% at 466 nm. Comparison of the curve with the nomogram indicates that on the average less than 10% of the light that excites the blue-sensitive cones is guided past or diffracted around their oil-droplets.