by Dr Dan Waniek, MD
Copyright © 2006 danwaniek.org
We have hypothesized that the iris may be able to transmit light through its stroma in spite of the irregularly dispersed, heavily absorptive pigment. This transmitted light, without interfering with the centro-retinal image because of total reflection on the anterior surface of the lens is, however, significant, and acts as a coded non-visual stimulus for the periphery of the retina.
The peripheral retina consists of a highly regular array of about seventy protrusions of nervous tissue, the processi dentati, in the pars plana of the ciliary body, collectively named the ora serrata.
This structure has not been understood so far in terms of vision : Indeed, campimetry fails to demonstrate correspondent protrusions in the margins of the visual field, even if there is positive histological evidence of normal receptive retinal structure in the ora serrata, to account for visual perception.
In our model the ora serrata is assumed to have a previously undescribed non-visual function. A critical test of these hypotheses would be to determine whether electro-retinography (ERG) can detect specific activity in the ora serrata when the surface of the iris, and not the pupil is light-stimulated.
This study was undertaken because of controversy existing between the conclusions of different approaches concerning the evaluation of iridology, the controversial diagnostic method based on clinical and empirical studies of the iridial morphology.