RESUMEN
Not all extraocular photoreceptors in the human brain have been identified or their functions determined. The efferent and afferent fibres between the orbital frontal cortex and the hypothalamus cannot be overlooked in the context of the neuro-endocrine-immune feedback loop. It is suggested here that there are extraocular photoreceptors in the orbital frontal cortex, conceivably crucial for immunoregulation. The orbital frontal cortex of 7 volunteers with rheumatoid arthritis (RA) was photostimulated through the roof of the orbits with filtered visible light in sessions of 12, 14 and 16 minutes for a period of 6 weeks. Within 5 weeks, a significant decrease in the rheumatoid factor titres of 6 subjects was observed together with marked clinical improvement in 4 cases.
