Biophysics of Vision Publisher



Shahjouei S^{1, 2} ; Amini M³
Source: Biophysics and Neurophysiology of the Sixth Sense Published:2019

Abstract

The function of the visual system is far beyond simply focusing the light beams to produce an image. To picture the adaptations to reduce the artifact and enhance the quality of the image, in the first section, we follow the light beams, as they are incident on the surface of the cornea to focus on the retina. We also explained the dynamic mechanisms to produce images of the objects in motion, at different distances, and under various luminances. In the second section, we further explore how the function of the visual system is interwoven with alterations in the magnetic field: visual system provides the components of the magnetic field perception, and the magnetic field affects visual properties. We also introduce the circadian rhythmicity and the modulating role of visual system on it, either directly or indirectly, through conveying the light/dark information and geomagnetic alterations to the brain. To offer a deeper understanding of the physical concepts and their application in biological events, we have provided five boxes. In Box 3.1, optical instruments for focusing a beam of light, fundamentals of refraction, and optical characteristics of the cornea and crystalline lens in normal and pathologic conditions are introduced. Box 3.2 explains diffraction and the role of pupil size in minimizing it. Box 3.3 provides detailed background on the geomagnetic perception and its interaction with visual functions and offers four mechanisms underlying the perception of slight magnetic field alterations. In Box 3.4, the key features of space weather and its manifestation on Earth's magnetic field and human physiology or pathologies are presented. Finally, Box 3.5 provides more information about circadian rhythms. © Springer Nature Switzerland AG 2019.