Visual Memory Research
The Genesis of Mnemonic Visual Systems 
Recurrent Dynamics in Excitable Media

Topic A1: Ocular Pressure Phosphenes and the Micro-Circulation Dynamics

Visible Structures:  Well-recognized in the literature, the entoptically-visible ocular anatomical structures include pre-corneal films, lenticular and vitreal opacities, the shadows of the retinal vascular arcades and the pre-retinal capillary net. 
     
Entoptic Circulatory Events:  Corpuscular capillary and arteriolar flow, the effects of hypoxia can be demonstrated subjectively by steady or by intermittent illumination, by local or global pressure, and by systemic circulatory or postural manipulations.

Auto-regulations to briefly-imposed ocular pressure:  This is a fatigueable one-time only a response demonstrable by the recovery of the initial amaurosis within 10−15 seconds delay, and again demonstrable only after several minutes respite.
   
Phosphenes:  Generated by mechanical ocular stimuli; vigorous sustained massage.                              
The following illustration of the subsequent entoptic perceptions depicts:

 1.) A bright yellow ellipse at the macula clearly delineated.
 2.) A diffuse yellow glow or mosaic pervades the general field, notably absent in the four oblique quadrants.




* This topography suggests that distortion of the globe is minimized at the sites of the orthogonal rectus muscles (yellow areas) with sufficient retinal corrugation displacement or mild edema in the un-supported regions to incur a Stiles-Crawford effect.

* The oval ring  at the macula is  evident.  see  Bernstein PS,  2004 " Resonance Raman measurement of macular carotenoids in the living human eye" . aul.bernstein@hsc.utah.edu 






Another  effect was seen in recumbency, with oblique shafts of setting- sun lighting, incur a Stiles-Crawford effect  with the  incidental onset  of Helmholtz Traveling Waves.