Posted by Retina -Phero [Phero] on November 28, 1999 at 12:26:12 {hcnmikA.FkdmhhsMJ.h2KYT0XYayR.}:
In Reply to: Questions for creationist posted by J.H. on November 28, 1999 at 09:25:18:
The question of the inverted retina:
Although it would appear at first sight that the inverted arrangement of the retina has disadvantages and is inefficient, in reality these objections amount to little. Even evolutionists concede that the inverted retina serves those creatures that possess it, very well; it affords them superb visual acuity. We have reviewed the necessity for this arrangement which turns on the nature of the photoreceptors.
The eyes are further shielded from excessive exposure to light and UVR by anatomical features: the normal horizontal orientation of the eyes when in the upright posture, the eyebrows (particularly for those with deep-set eyes), the nose and the cheeks. But any natural defence system can be overwhelmed and so it is sensible when necessary (just as it is to wear extra clothing in cold weather) to wear or use extra protection against UVR and blue light; all the more is this so with the depletion of our ozone layer.
Light at various wavelengths is capable of very damaging effects on biological machinery. The retina, besides being an extremely sophisticated transducer and image processor, is clearly designed to withstand the toxic and heating effects of light. The eye is well equipped to protect the retina against radiation we normally encounter in everyday life. Besides the almost complete exclusion of ultraviolet radiation by the cornea and the lens together, the retina itself is endowed with a number of additional mechanisms to protect against such damage:
Phero