Not totally blind spot, according to Scientific Reports 26 June 2015 doi:10.1038/srep11862. The “blind spot” is a small area in the retina (the light sensitive layer at the back of the eye) where nerve fibres are gathered together to form the optic nerve. It has been assumed the blind spot is insensitive to light because it has no rods and cones, which are the light sensitive cells that are used to convert light to electrical signals. Although this spot is in the middle of our visual field, we do not perceive a black hole in our view of the world because the brain can fill in the deficit by using visual information from the other eye, and from the surrounding retina in the same eye.
Two Japanese scientists have now discovered that although the blind spot has no rods and cones, it seems to have some light sense. In order for us to see well our eyes need to adjust to the amount of light by changing the size of the pupil in the front of the eye. This is controlled by an unconscious reflex that constantly adjusts the pupil in response to changing light. The scientists made a careful study of how the eye responds to variations in intensity and colour of light, and found that the blind spot “unexpectedly” contributes to the pupillary light reflex.
Their experiments involved shining a disc of light onto the blind spot and surrounding retina, and then shining a ring of light with the same outer diameter of the disc, but with a dark central region the same size as the blind spot. Therefore, the ring was only shining light on the rods and cones around the blind spot, but not onto the blind spot itself. They found the disc, which exposed the blind spot to light, elicited a larger pupillary response than the ring which did not shine light onto the blind spot.
They concluded: “These results suggest that some physiological mechanism, presumably the retinal cells containing the photopigment melanopsin, receives the light projected inside the blind spot and enhances pupillary light reflex”.
Editorial Comment: The blind spot has been the subject of scorn by atheists who use it as an example of “unintelligent design”. Richard Dawkins was particularly scathing in his book The Greatest Show on Earth where he described the blind spot as “the design of a complete idiot”. (See our report An Idiotic Eye here) However, even Dawkins admitted that the blind spot does not hinder our conscious vision because our brains compensate for it. Now he should ‘humbly’ concede that it is not completely useless. We may not be aware of the pupillary light reflex, but it is essential for good vision. Too much light can damage the retina, so it is important that the eye responds rapidly to bright light. Having the “blind spot” involved in the system makes the light reflex more efficient, and reminds us that the eye is exquisitely designed by a complete genius.
How tragic that Dawkins and his colleagues cannot see this – but the problem is not their eyes, but in rebellious hearts and minds that do not want to acknowledge the Creator and Saviour, who will also be their Judge. (Ref. vision, reflexes, optics)
Evidence News vol. 15, No. 12
15 July 2015
Creation Research Australia