Eye References In The Homeric Epics

Sensory deprivation IS effective, and for those who can will themselves into a state of such intense meditation as will exclude incoming signals from the environment, the computer model provides a simple analogy. With aging, a prominent white ring develops in the periphery of the cornea called arcus senilis. Aging causes laxity, downward shift of eyelid tissues and atrophy of the orbital fat. These changes contribute to the etiology of several eyelid disorders such as ectropion, entropion, dermatochalasis, and ptosis.

Melatonin did, in fact, suppress physiological sexuality in mammals. If test animals were stimulated to manufacture excessive amounts of melatonin, their gonads and ovaries tended to become reduced in size, to shrink, to atrophy. The estrous, or fertility, cycle in females could likewise be altered experimentally by doses of melatonin. Various eye care professionals, including ophthalmologists (eye doctors/surgeons), optometrists, and opticians, are involved in the treatment and management of ocular and vision disorders. A Snellen chart is one type of eye chart used to measure visual acuity.

Other risk factors, such as chemical toxins/irritants (e.g. amines, formaldehyde, acetaldehyde, acrolein, N-decane, VOCs, ozone, pesticides and preservatives, allergens, etc.) might cause eye irritation as well. The approximate field of view of an individual human eye (measured from the fixation point, i.e., the point at which one’s gaze is directed) varies by facial anatomy, but is typically 30° superior , 45° nasal , 70° inferior , and 100° temporal . For both eyes combined visual field is 135° vertical and 200° horizontal. It is an area of 4.17 steradians or square degrees for binocular vision. When viewed at large angles from the side, the iris and pupil may still be visible by the viewer, indicating the person has peripheral vision possible at that angle. A person’s eye color results from pigmentation of a structure called the iris, which surrounds the small black hole in the center of the eye and helps control how much light can enter the eye.

At this point, the eye is moved back to the point where it first saw the train . The Optokinetic reflex stabilizes the image on the retina through visual feedback. It is induced when the entire visual scene drifts across the retina, eliciting eye rotation in the same direction and at a velocity that minimizes the motion of the image on the retina. When the gaze direction deviates too far from the forward heading, a compensatory saccade is induced to reset the gaze to the centre of the visual field.

Through it we may find a means of understanding more clearly the roots of madness and of helping the insane to return to the world of commonplace reality. For most of us, most of the time, our world is a Darwinian environment. We must manipulate ourselves within it, or attempt to manipulate it in order to survive. These survival needs tend to color our appreciation of this world, and we are continually making judgments about it.