Page 41 - Miracle in the Eye

HARUN YAHYA

sensitivity to a maximum of between 500,000 and 1,000,000 times. This factor
is adjusted automatically, according to the surrounding brightness in the en-
vironment.
In order for the retina to register an image, it must determine the dark
and light spots upon the object being viewed. For that reason, sensitivity
must be adjusted so that the receptors respond always to the brighter points,
not the darker ones.
Imagine, for example, that you're stepping out into bright daylight, hav-
ing just sat through a film at the cinema. Everything you look at, even spots
that normally appear dark, will seem unusually bright and because of low
contrast you will see a lot of light colors. This is inadequate vision, of course,
and fixes itself once the retina adjusts itself so that its receptors are not over-
stimulated by the darker spots in your field of vision. When you walk into a
darkened room, now your retina's sensitivity is very low and therefore, even
the brighter spots on objects cannot stimulate it. But once your retina adjusts
to the dark, the bright spots do register. The retina can adjust to extreme light
and dark. And even though sunlight is 30,000 times brighter than moonlight,
your eye is able to adjust and see in environments illuminated by either
source of light. 8

The Lens: The Eye's Focusing Mechanism
The lens, situated immediately behind the iris and the pupil, breaks
down incoming beams of light and focuses them on the retina. Made of pro-
tein fibers, the lens is transparent, hard but slightly elastic and yellowish in
color. Similar to a magnifying glass, the center of the lens is convex in struc-
ture.
With the aid of muscles surrounding it, the lens is able to change shape,
allowing it to adjust itself according to the angle light comes in, ensuring it is
always directed onto the retina. When you look at a point close to your eyes,
muscles flex your lens into a more convex position. But when you view a dis-
tant point, the muscles relax, stretching the lens into a flatter configuration
and thus clarifying the images of distant objects.
Like the cornea, the lens contains no blood vessels, and so it is nourished
by the eye fluid.

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