A

Vision

The eye transforms light into electric impulses

Clear view. The image focus happens on the retina

Blurry vision due to myopia. The image focus happens before the retina

85% of our relationship with the world and our daily activities depend directly to our vision and the perfect functioning of the eyes. Visual problems, when not identified, may trigger low school performance for many children. Some signs: squinting to see better, greater sensitivity to light, headaches after visual efforts such as reading, or getting too close to read. Myopia, hypermetropia and astigmatism are visual problems which need the use of glasses with corrective lenses.

B

We can compare our vision with the functioning of a photography camera. The light goes through two lenses (the cornea and the crystalline) and the image has to arrive clearly in the macula (central area of the retina). The retina has countless photoreceptive neurons that convert the light signals into electric impulses, transmitted to the brain by the optic nerve. The brain interprets and makes sense of the images.

There are three tunics in the eye:
External or fibrous tunic - made up of the cornea and sclera.
Intermediate or vascular tunic - formed by the iris, choroid and the ciliary body.
Internal or nervous tunic - constituted by the retina which is sensible to luminous signals.

C

Position of the ocular globe in the right eye socket

A lot of protection!! The eye is in the eye orbit, surrounded by fat and it’s protected by the eyelids, eyelashes and by the eyebrows of particles that may harm it. The most dangerous sports to the eyes are the ones that use small balls (tennis, squash and golf, for example).

D

Position of the external ocular muscles, forming the muscular cone

Lateral view of the intra-orbital structures (right eye)

 Part of the eye where the lachrymal gland and the insertion of muscle in the sclera is evident

The human eye is approximately the size of a ping-pong ball. It’s about 2,54 cm in diameter.

The eye has 6 muscles. One to each direction.

E

Glaucoma is the greatest cause of irreversible blindness. Associated with the increase of eye pressure, it causes progressive loss of the visual field, being generally more common after 40 years of age. Glaucoma is asymptomatic (doesn’t itch, doesn’t hurt, doesn’t burn, doesn’t irritate the eyes). That’s why it’s necessary to make the ophthalmologic exam yearly.

Normal eye. The optic nerve emerges from the retina. The cup (excavation) is in the center of the optic nerve and it’s the area where there’s an absence of nervous tissue

Glaucoma. There is an increase in the cup (excavation) of the optic nerve

Advanced glaucoma. There is great loss of fibers of the optic nerve. The cup (excavation) is almost total