Submit Article
Asian Journal of Physics Vol 32, Nos 3 & 4 (2023) A1-A10

From waveguides to directional antennas – understanding the optics of retinal photoreceptors

Brian Vohnsen
Advanced Optical Imaging Group, School of Physics,
University College Dublin, Dublin 4, Ireland

Dedicated to honor of Prof Jay M Enoch

The Stiles-Crawford effect (i.e., the psychophysical Stiles-Crawford effect of the first kind) has remained somewhat of an enigma in vision science since its discovery 90 years ago. It is often treated as a curiosity, or even a minor effect, but the reality is that at a fundamental level it is so much more. It represents the last optical process in the eye where photon absorption triggers the visual pigments in the cones and rods resulting in neural signals and, ultimately, a visual sensation via the visual cortex. Naturally, most ophthalmic studies focus on the anterior eye, the cornea and lens, that determines how light is focused onto the posterior eye and retina. The latter is typically considered as a screen onto which an image of the outside world is projected. Nonetheless, we can only hope to comprehend vision and the optics of the eye once the detectors, i.e., the photoreceptors and their visual pigments, are included. This has been central to much of Prof Jay M Enoch’s work. In my own research, I was initially intrigued by a study on the relationship between the psychophysical Stiles-Crawford effect and the directionality in backscattered light in the pupil plane often referred to as the optical Stiles-Crawford effect. This led me to revisit waveguide models of photoreceptors in what I initially thought would be just a single study. Yet, as a pebble in the shoe, it has kept returning for nearly two decades posing additional questions. Now, we may be at the end of the road in terms of understanding the Stiles-Crawford effect of the first kind, but we are still only in the infancy of comprehending how this vital last optical step in our visual system adapts to changes in relation to age and to disease. Only when comprehending its adaptability and function, can we hope to fully separate optical effects from neural factors to obtain an entirely satisfactory and accurate model of vision. © Anita Publications. All rights reserved.
Keywords: Photoreceptors, Waveguides, Scattering, Leakage, Stiles-Crawford effect, Directionality, Ellipsoid.

Peer Review Information
Method: Single- anonymous; Screened for Plagiarism? Yes
Buy this Article in Print © Anita Publications. All rights reserve

References

  1. Brücke E W, Ueber die physiologische Bedeutung der stabförmigen Körper und der Zwillingszapfen in den Augen der Wirbelthiere, Archiv für Anatomie, Physiologie und wissenschaftliche Medicin, (1844)444–451.
  2. Stiles W S, Crawford B H, The luminous efficiency of rays entering the eye pupil at different points, Proc R Soc Lond B, 112(1933)428–450.
  3. Vohnsen B, The retina and the Stiles-Crawford effects. In: P. Artal (Ed). Handbook of Visual Optics: Fundamentals and Eye Optics, Vol I. (CRC Press), 2017, Ch 18.
  4. Nilagiri V K, Suheimat M, Lambert A J, Turpin A, Vohnsen B, Atchison D A, Subjective measurement of the Stiles-Crawford effect with different field sizes, Biomed Opt Express, 12(2021)4969–4981.
  5. Vohnsen B, Photoreceptor waveguides and effective retinal image quality, J Opt Soc Am A, 24(2007)597–607.
  6. Vohnsen B, Carmichael A, Sharmin N, Qaysi S, Valente D, Volumetric integration model of the Stiles-Crawford effect of the first kind and its experimental verification, J Vision, 17(2017)18; doi:https://doi.org/10.1167/17.12.18.
  7. Vohnsen B, The impact of aberrations in a 3D retinal model eye, Proc SPIE, 11814, Current Developments in Lens Design and Optical Engineering XXII (2021)1181405; doi.org/10.1117/12.2594117.
  8. O’Brien B, A theory of the Stiles and Crawford effect, J Opt Soc Am, 36(1946)506–509.
  9. O’Brien B, Vision and resolution in the central retina, J Opt Soc Am, 41(1951)882–894.
  10. Enoch J M, Fry G A, Characteristics of a model retinal receptor studied at microwave frequencies, J Opt Soc Am, 48(1958)899–911.
  11. Enoch J M, Stiles W S, The colour change of monochromatic light with retinal angle of incidence, Opt Acta, 8 (1961)329–358.
  12. Stiles W S, The luminous efficiency of rays entering the eye pupil at different points and a new colour effect, Proc R Soc Lond B, 123(1937)90–118.
  13. Enoch J M, Wave-guide modes in retinal receptors, Science, 133(1961)1353–1354.
  14. Enoch J M, Optical properties of the retinal receptors, J Opt Soc Am, 53(1963)71–85.
  15. Hecht J, City of light: the story of fiber optics (Oxford University Press), 2004.
  16. Snyder A W, Pask C, The Stiles-Crawford effect: Explanation and consequences, Vision Res, 13(1973)1115–1137.
  17. Laties A M, Enoch J M, An analysis of retinal receptor orientation. I. Angular relationship of neighboring photoreceptors, Invest Ophthalmol, 10(1971)69–77.
  18. Choi S S, Garner L F, Enoch J M, The relationship between the Stiles-Crawford effect of the first kind (SCE-I) and myopia, Ophthalmic Physiol Opt, 23(2003)465–472.
  19. Kono M, Enoch J M, Strada E, Shih P, Srinivasan R, Lakshminarayanan V, Susilasate W, Graham A, Stiles-Crawford effect of the first kind: Assessment of photoreceptor alignments following dark patching, Vison Res, 41(2001) 103–118.
  20. Smallman H S, MacLeod D I A, Doyle P, Vision: Realignment of cones after cataract removal, Nature, 412(2001) 604–605.
  21. Burns S A, Wu S, Delori F, Elsner A E, Direct measurement of human-cone-photoreceptor alignment, J Opt Soc Am, 12(1995)2329–2338.
  22. Roorda A, Williams D R, Optical fiber properties of individual human cones, J Vis, 2(2002)404–412.
  23. Gao W, Cense B, Zhang Y, Jonnal R S, Miller D T, Measuring retinal contributions to the optical Stiles-Crawford effect with optical coherence tomography, Opt Express, 16(2008)6486–6501.
  24. Rativa D, Vohnsen B, Analysis of individual cone-photoreceptor directionality using scanning laser ophthalmoscopy, Biomed Opt Express, 2(2011)1423–1431.
  25. Morris H J, Codona J L, Blanco L, Doble N, Rapid measurement of individual cone photoreceptor pointing using focus diversity, Opt Lett, 40(2015)3982–3985.
  26. Qaysi S, Valente D, Vohnsen B, Differential detection of retinal directionality, Biomed Opt Express, 9(2018) 6318–6330.
  27. Vohnsen S, Iglesias I, Artal P, Directional imaging of the retinal cone mosaic, Opt Lett, 29(2004)968–970.
  28. Marcos S, Burns S A, He J C, Model for cone directionality reflectometric measurements based on scattering, J Opt Soc Am A, 15(1998)2012–2022.
  29. Vohnsen B, Iglesias I, Artal P, Guided light and diffraction model of human-eye photoreceptors, J Opt Soc Am, 22(2005)2318–2328.
  30. Vohnsen B, Visual Implications of Retinal Photoreceptor Waveguiding, Proc ICO Topical Meeting on Optoinformatics/Information Photonics, (St. Petersburg, Russia), 2006.
  31. Vohnsen B, A short history of optics, Phys Scr, (2004)75; doi. 10.1238/Physica.Topical.109a00075.
  32. Enoch J M, The fascinating early history of optics! Archaeological optics 2009: Our knowledge of the early history of lenses, mirrors, and artificial eyes!, Proc SPIE, 7428, Current Developments in Lens Design and Optical Engineering X 742803 (2009); doi.org/10.1117/12.828453.
  33. Vohnsen B, On the spectral relation between the first and second Stiles–Crawford effect, J Mod Opt, 56(2009) 2261–2271.
  34. Vohnsen B, Rativa D, Absence of an integrated Stiles–Crawford function for coherent light, J Vision, 11(2011)19; doi.org/10.1117/12.828453.
  35. Drum B, Additivity of the Stiles–Crawford effect for a Fraunhofer image, Vision Res, 15(1975)291–298.
  36. Calvo M L, Lakshminarayanan V, Initial field and energy flux in absorbing optical waveguides. I. Theoretical formalism, J Opt Soc Am, 4(1987)1037–1042.
  37. Valente D, Vohnsen B, Retina-simulating phantom produced by photolithography, Opt Lett, 42(2017)4623–4626.
  38. Vohnsen B, Directional sensitivity of the retina: A layered scattering model of outer-segment photoreceptor pigments, Biomed Opt Express, 5(2014)1569–1587.
  39. Francia G T D, Retina cones as dielectric antennas, J Opt Soc Am, 39(1949)324–324.
  40. Ball J M, Chen S, and W. Li W., Mitochondria in cone photoreceptors act as microlenses to enhance photon delivery and confer directional sensitivity to light, Sci Adv, 8(2022)eabn2070; doi.10.1126/sciadv.abn2070.
  41. Lochocki B, Rativa D, Vohnsen B, Spatial and spectral characterisation of the first and second Stiles–Crawford effects using tuneable liquid-crystal filters, J Mod Opt, 58(2011)1817–1825.
  42. Lochocki B, Vohnsen B, Defocus-corrected analysis of the foveal Stiles–Crawford effect of the first kind across the visible spectrum, J Opt, 15(2013)125301; doi. 10.1088/2040-8978/15/12/125301.
  43. Martins A C, Vohnsen B, Analysing the impact of myopia on the Stiles-Crawford effect of the first kind using a digital micromirror device, Ophthal Physiol Opt, 38(2018)273–280.
  44. Vohnsen B, Geometrical scaling of the developing eye and photoreceptors and a possible relation to emmetropization and myopia, Vision Res, 189(2021)46–53.
  45. Bang S P, Lyu J, Ng C J, Yoon G, Visual Axis and Stiles–Crawford Effect Peak Show a Positional Correlation in Normal Eyes: A Cohort Study, Invest Ophthalmol Vis Sci, 63 (2022); doi.org/10.1167/iovs.63.11.26. art12.
  46. Miloudi C, Rossant F, Bloch I, Chaumette C, Leseigneur A, Sahel J.-A, Meimon S, Mrejen S, Paques M, The Negative Cone Mosaic: A New Manifestation of the Optical Stiles-Crawford Effect in Normal Eyes, Invest Ophthalmol Vis Sci, 56(2015)7043–7050.
  47. Schmidt B P, Boehm A E, Tuten W S, Roorda A, Spatial summation of individual cones in human color vision, Plos One, (2019)0211397; doi.org/10.1371/journal.pone.0211397.
  48. Boyle K C, Chen Z C, Ling T, Pandiyan V P, Kuchenbecker J, Sabesan R, Palanker D, Mechanisms of light-induced deformations in photoreceptors, Biophys J, 119(2020)1481–1488.
From-waveguides-to-directional-antennas–understandingDownload

Related Posts