The authors also compare the light experiences to physiologically researched “simple visual hallucinations” which are induced by sensory deprivation, perceptual isolation and disorders of the visual system (Charles Bonnet syndrome). These hallucinations can be distinguished the same way as the meditation-induced lights, i.e. in discrete lightforms like colored spots or dots of light and flashes of light (phosphenes and photopsia), and patterned and diffuse phenomena like lattices, grids, cobwebs, branching forms, zigzag patterns, visual snow, as well as general brightening, shimmering and mist or fog, among others. These light experiences are neurobiologically explained as an effect of the homeostatic plasticity, a mechanism by which neurons regulate their intrinsic excitability in order to maintain stable activity and firing rates: When sensory inputs are attenuated or deprived, this decrease is compensated by an increase of neuronal excitability. Neurons switch to more frequent and spontaneous firing which is experienced subjectively as light hallucinations.
Since Buddhist meditation practices often take place in social isolation or in groups with minimal social interaction; and since meditation means to restrict attention to monotonous, homogenous or repetitive stimuli, the authors understand the meditation-induced light experiences to be a result of that sensory attenuation or deprivation. Furthermore, sensory attenuation increases neuroplasticity – i.e. the adaption of the neuronal system to behavioral, environmental or physiological changes; therefore, the authors suggest that the meditation-induced light experience indicate periods of enhanced neuroplasticity in which cognitive and therapeutic processes are facilitated. Finally, the authors propose to further study the entoptic light phenomena in order to measure meditative proficiency or expertise.
Subjective visual light phenomena are studied best by observing them during different states of consciousness. However, as soon as we start thinking about them, it is rewarding to understand what different cultures and systems of meaning and knowledge have to contribute, in order to get a more complete picture. The study by Jared R. Lindahl and his team works in that direction. The authors take entoptic phenomena seriously as an effect of a spiritual practice, locate them in a concrete religious tradition, but also go beyond that and compare them to physiologically researched light phenomena.
The study reveals some parallels between Buddhist meditation and the practice of consciousness intensification in the seers’ sense: both take entoptic light phenomena as meditation objects and understand them as indications of a certain meditative expertise. This also shows that entoptic phenomena can be intensified not only through ecstatic (shamanistic) practices (Tausin 2010, 2012), but also through practices of calm and focused attention or meditation; whether this leads to the penetration of the layers of consciousness, to the “zoom-effect”, to “macroscopic” seeing and, eventually, to entering the picture as a whole, is unclear to me and requires further investigation. From a neurological perspective, a relationship between light experiences and enhanced neuroplasticity is established: Seeing entoptic phenomena goes along with increased receptiveness and openness for processes of learning, insight and healing. This is also claimed by the seers as a side effect of the “path in the shining structure”.
Eye floaters are not mentioned in that study. That’s comprehensible since in physiology, floaters are still deemed vitreous opacities and not understood in neurological terms (Tausin 2011). However, the light phenomena descriptions by both meditators and Buddhist literature contain “discreet lightforms” that point to floaters, most likely the “white or luminous spots or spheres”, the “clusters of pearls or gems” and the “moon’s or sun’s disks”. Finally, this study is another clue for the growing awareness of the individual, cultural and spiritual meaning of entoptic phenomena.
Thank you, Jackson Peterson (www.wayoflight.net), for that hint!