[Role of cellular organoids in photoreceptor optics (studies on microwave models)]

Action of the refracting structures of the photoreceptor inner segment on the receptor directional sensitivity was studied with the microwave models. Models of photoreceptor cells enlarged by 15 000 times were made of polystyrene foam and irradiated by microwaves (5.7-8.3 mm). Focusing structures (cone ellipsoid and oil drop) increase the power propagating along the photoreceptor outer segment when illuminated axially. However, they sharply increase the directionality of the cell, so that there is no overall gain in sensitivity in the case of a large pupil. It is supposed that the main role of the focusing structures is to narrow the directional sensitivity curve of the photoreceptor, to decrease the effects of the scattered light and to increase the depth of the focus.