Photons from bovine rod
The time is close that biophysical picture idea in early retinotopic V1 and V2 cortex will be right.
Because phosphenes can be induced for example via TMS in V1 and V2 without any retinal photon perception, it suggests that early retinotopic areas can perform the same process without retinal photon perception. Thus, since retinal and cortical induced phosphenes are required to have a common molecular biophysical basis, if it can be demonstrated that perception of cortical induced phosphenes is due to bioluminescent photons, intrinsic regulated biophotons in early retinotopic visual system can be seen to serve as a natural biophysical substrate of visual perception and imagery.
Here is a new paper that support retinal phosphenes-like sensation due to the bioluminescent photons.
Naricil, Paci M, et al.. Bovine rods rhodopsin:1. Bleaching by luminescence in vitro by recombination of radicals from polyunsaturated fatty acids. Free Radic Biol Med 2012 May 24. [Epub ahead of print]
Rod Outer Segment of photoreceptors are characterized by rhodopsin, a membrane protein surrounded by phospholipids containing a very high concentration of polyunsaturated fatty acid. These are subjected to propagate free radicals-initiated by peroxidation whose recombination is eventually associated with light emission as chemiluminescence. The results herewith reported indicate that this effect is able to produce an isomerization of the retinal (bleaching effect) of the rhodopsin similar to that induced by light in normal vision. In vitro experiments on detergent suspended Rod Outer Segment from bovine eyes, using an enzymatic source of radicals Xanthine-Xanthine oxidase, have been carried out. The results indicate that the mechanism proposed is likely because it is able to bleaching rhodopsin of RdOS due to its extraordinary sensitivity. Thus this mechanism is, also, a possible explanation for anomalous visual effects like flash lights (phosphenes-like) perceived by humans. The functionality of the rhodopsin in the RdOS has been first tested by visible light. Rhodopsin reactivation after bleaching has been obtained adding cis-retinal to the suspension, demonstrating the reversibility of the bleaching process. A special experimental system was developed to observe the bleaching from luminescence by radical recombination avoiding physical contact between Rod Outer Segment suspension and radicals, to prevent radical induced damage and modifications of the delicate structure of the Rod Outer Segment.