Stiles–Crawford effect of the first kind: influence of the outer segment disc structure of human retina cones

Abstract

This study analyses the way that the disc structure of the cone outer segment of the human retina affects light propagation through the cones, and how it influences the Stiles–Crawford effect of the first kind (SCE I). For this, we have used the finite-difference time-domain method (FDTD), enabling a numerical solution of Maxwell's equations. The intensity patterns at the cone endface are then compared with those found using the cone model with a homogeneous outer segment used in previous studies. The results for the new model, based on segments of optical fibre, show greater confinement of light propagating through the cone, and higher light intensity when the light strikes the entry face of the cone at certain angles.

Keywords:

• Stiles–Crawford effect
• human photoreceptor
• model cone
• FDTD method
• optical fibre

Acknowledgements

The authors wish to thank Begoña Martínez and Rebecca Hendry from Matiz Soluciones Lingüísticas and David Nesbitt for translating the text into English.