Function of the human eye


Vista Alpina 

Eye Center

Bahnhofplatz 1a
3930 Visp

Phone 027 946 70 00

Fax 027 946 70 03

Send an e-mail



Monday - Friday:

8am - 12pm

1pm - 7.30pm

(On Tuesdays, Wednesdays and

Fridays until 6pm)

On Saturdays:

8am - 12pm


by phone


Vista Alpina

Eye Center

Rue du Bourg 3
3960 Sierre

Phone 027 455 34 04

Fax 027 455 34 77

Send an e-mail



Monday, Wednesday, Friday:

8am - 12pm

12.30pm - 5pm

(Monday 12.45pm)


7am - 12pm

12.45pm - 7pm


8am - 12pm

12.45pm - 5.30pm

Saturday: closed


by phone


Augenzentrum Vista Alpina AG and the services provided by Augenzentrum Vista Alpina are not legally or otherwise affiliated with Vista Klinik AG, Laser Vista AG, Vista Klinik Net AG or Vista Diagnostics AG.

“Seeing" is the most complex of the six senses. In order for the brain to be able to get a picture of the surroundings, the eye must convert light into nerve impulses, which are subsequently routed through the optic nerve.


Here, different parts of the eye have specific tasks. The primary ones being:


  • the iris

  • the cornea

  • the lens

  • the retina

The part of the eye giving it colour is called the iris. It consists of muscles, allowing it to enlarge and contract the pupil. The pupil is the round black opening at the centre of the iris through which light rays enter the eye. The iris and pupil control how much light is allowed to enter the eye.


When it is very bright, the pupil contracts so we are not blinded. In the dark, it enlarges to allow as much light to enter as possible, so we can recognise our surroundings. The iris and the pupil are covered by a translucent layer: the cornea.

Structure human eye, Vista Alpina Eye Center Valais
Aufbau des menschlichen Auges, Vista Alpina Augenklinik

Along with our eyelids, eyelashes and the tear fluid, it particularly serves protecting the eyes from foreign objects and injuries.


However, the cornea is also important for seeing: The light rays entering the eye must pass through it and are already broken here.


There is fluid between the cornea and the lens of the eye; the aqueous humour. It cleans the eye and supplies the cornea and lens with nutrients.

The inside of the eye

After light rays have passed through the pupil, they reach the lens. Here, the incoming light is bundled, similar to a camera. The lens is attached to fibres and muscles, which pull the lens, allowing it to change its shape.


In doing so, the eye can adjust to “near" or “far" - similar to a camera or binoculars. By the lens adjusting itself, it bundles the incoming light rays so they produce a sharp image on the retina. This process is called accommodation.

Structure of human eye, cones, red, Vista Alpina Eye Center Valais

The back of the inner eye is lined with the retina. It has over 120 million sensory cells, which convert incoming light rays into nerve signals. The retina can be compared to the chip inside a camera, which records the image as many dots.


There are two types of sensory cells - rods and cones:

  • The rods allow for “light-dark vision" in twilight and at night.

  • The cones are responsible for sharp vision and seeing colour.

These two types of sensory cells are not equally spread across the retina. The cones are densest at the centre of the retina, the “yellow spot" (macula). This is the area, which allows the sharpest vision in bright light and which our attention focuses on.


The nerve signals from the sensory cells are then sent from the optic nerve to the brain, where they are assembled into a picture of the surroundings.

SIWF-ISFM certificate ophthalmo surgery Vista Alpina Eye Center
Hospital certificate Vista Alpina Eye Center

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