Fine tuning of ‘backward’ eye is vital for colour vision
Evolutionists such as Richard Dawkins have long claimed that our eyes are wired ‘backwardly’, allegedly something which no intelligent designer would do. That is, the light receptor cells are behind the nerves, which supposedly obstruct the light path.
In reality, in the last few years, researchers have shown that light doesn’t go through the nerves, but is instead funnelled through Müller glial cells.1
These act like a fibre optic plate that increases image sharpness, so “The retina is revealed as an optimal structure designed for improving the sharpness of images.”2,3 Furthermore, they help to separate out the three primary colours, so that red and green light is funnelled to the colour-sensitive cones. The other type of light receptor, rods, are good for night vision, but weaker at detecting green and especially red light, so the Müller cells scatter blue light on to them.4,5
Much of this new research comes from Technion, the Israel Institute of Technology, in the lab of Dr Erez Ribak, an astrophysicist who turned from studying stars to studying eyes. He has now shown that the Müller cells must be just the right height and width to filter the different colours correctly: “If the retina is too thick or too thin, it’s not effective.” He proved this by shining light of different colours into human and guinea pig retinas, showing how the light was guided.6 Ribak says:
“[T]he retina of the eye has been optimised so that the sizes and densities of glial cells match the colours to which the eye is sensitive (which is in itself an optimisation process suited to our needs). This optimisation is such that colour vision during the day is enhanced, while night-time vision suffers very little.”6
Mark Hankins, a professor of visual neuroscience at the University of Oxford, pointed out even another reason for the backward wiring: “clearing of worn-out cell components and having access to a fuel supply of light-sensitive molecules.” These functions are provided by a layer behind the light receptors, called the retinal pigment epithelium (RPE), which means that the nerves can’t also be behind the receptors. Of course, long ago, creationist ophthalmologist Dr George Marshall pointed out this very thing in the pages of this magazine.7 And other researchers have adduced from analysing baby zebrafish eyes, “evidence that the inverted retina actually is a superior space-saving solution, especially in small eyes.”8
References and notes
- Labin, A.M. and Ribak, E.N., Retinal glial cells enhance human vision acuity, Physical Review Letters 104, 16 April 2010 | doi:10.1103/PhysRevLett.104.158102. Return to text.
- New eye discovery demolishes Dawkins, Creation 32(4):10, 2010; creation.com/mueller-v-dawkins. Return to text.
- Labin, A.M. et al., Müller cells separate between wavelengths to improve day vision with minimal effect upon night vision, Nature Communications 5(4319), 8 July 2014 | doi:10.1038/ncomms5319. Return to text.
- Eyesight: Separating light for better sight, Nature Communications 9 July 2014 (comment on Labin et al., Ref. 3). Return to text.
- ‘Bad design’ of eye improves day vision without sacrificing night vision, Creation 37(1):8, 2015. Return to text.
- Ribak, E., Look, your eyes are wired backwards: here’s why, theconversation.com, 14 March 2015. Return to text.
- Marshall, G. (interviewee), An eye for creation, Creation 18(4):19–21, 1996; creation.com/marshall. Return to text.
- Kröger, R.H.H. and Biehlmaier, O., Space-saving advantage of an inverted retina, Vision Research 49(18):2318–2321, 9 September 2009 | doi:10.1016/j.visres.2009.07.001.