Eye and vision

 

Feel and count the blinks of your eyes

 

- How many times have you blinked in a minute?
- Check and adjust the frequency on the table.
- is generally considered normal blink every 3 seconds, or about 20 times per minute.

 

DATE
         
HOUR
                   
blinks in a minute
                   


Bbeating frequently eyelids with a voluntary movement produces a relaxing effect and helps the natural function of:

- lubrication of eyes
- giving the eyes a moment of rest, when the eyelids are lowered.

DX
SX
DX-SX


How do you feel
the right eye?
Draw it.


How do you feel
the left eye?
Draw it.


How do you feel
the both eyes?
Draw it.

Before the A.T.M. lesson
Before the A.T.M. lesson
Before the A.T.M. lesson

 

Structure of Eye

The eye is a complex sense organ located within the orbital cavity. Inside, protected by a shell, there are: a layer of receptors, a lens, a system of neurons capable of conducting impulses from the retina to the visual cortex generating visual sensations.

1 - sclera;
2 - ciliary body;
3 - iris;
4 - pupil, and anterior chamber filled with aqueous humour;
5 - optical axis;
6 - line of sight;
7 - cornea;
8 - crystalline lens;
9 - choroidea;
10 - nervus opticus;
11 - optic disc;
12 - fovea;
13 - retina;
14 - corpus vitreum

 

A window on the world gathers images and puts us in touch with reality. The inner tunic of the eye is formed by a thin layer of nervous tissue that contains specific receptors of light, capable of transmitting the stimulus, translated in nervous current, to the brain via the optical nerve.

The name of rod and cone photoreceptors comes from the particular form it takes.

Sezione schematica della retina

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(Il grande libro del corpo umano Rizzoli pag 255)

Eye and camera

The eye like a camera.

1 - They are made of a dark room equipped with a lens. Within the eye the black coating of the darkroom is formed by the choroid and biconvex lens, whose curvature is variable. In the camera the room is covered with a reflective material and the glass lens has a fixed curvature.

2 - Within the eye of the lens projects an inverted image on a surface sensitive to light: the retina while within the camera it does on a photographic film.

3 - Light enters the eye through the pupil adjusted by the iris, wihithin the camera through a hole controlled by a diaphragm.

4 - In the eye of the image is took in focus through the muscle mass of the lens, the camera image is focused through the bellows.

5 - The images are recorded through a chemical reaction caused by light in the eye, the reaction occurs in the photosensitive cells of the retina, within the camera it happens upon the film.

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Photographic film retina of the eye