The eye is an important organ in the human sense. We get our information with the help of light and the eye. This information is forwarded via the optic nerve to the brain. Only with the help of the eye we are able to see and perceive visual images.
Structure of the eye
The eye is composed of:
- the eyeball (Bulbus oculi)
- fenders (eye socket, eyelids, conjunctiva, lacrimal apparatus)
- the musculoskeletal system (muscles of the eye, Tenon's capsule)
- the optic nerve
All four main parts of the eye cover different functions. The eyeball is responsible for perceiving light stimuli from the outside. The eye is the shape of a sphere and is slightly smaller than a table tennis ball. Inside the eyeball there is the lens, the vitreous body and the eye chambers. The wall of the eyeball is composed of the outer, the middle and the inner eyeball. The latter is also known as the retina.
The visual process
While focusing sight comes through the cornea and into the middle layer of the eyeball wall. The iris, which is colored by pigments, is responsible for our eye color.
The iris works like the diaphragm of a camera: two muscles constrict or dilate the pupil and regulate the amount of light in the eye. Behind the iris, the light hits the lens and is focused. The resulting image is there on the retina or the inner wall layer of the eyeball. Via the optic nerve, the image information retained on the retina is forwarded to the brain
The optic nerve connects the eye to the brain, which allows the person to perceive an image. The eyes mobility is controlled by four straight and two oblique eye muscles. These muscles allow the movement of the eyeball in all different directions.
What is a visual impairment?
A visual impairment can have diverse causes and symptoms. Stress and fatigue can cause poor vision. People of all ages may be affected by eye disease and visual impairment. The occurance of these diseases and impairments is rapidly growing among people all ages.
Not all visual impairments are created equal. Just because you have a visual impairment, does not mean you have, or will have, a more serious eye disease. There is a definitive distinction between refractive vision loss or impairment and more serious eye diseases.
The most common refractive finds are myopia and hyperopia.
With myopia, the eyeball is too long and the object is displayed in front of the retina. A diverging lens (concave lens) may correct this common vision problem.
In the case of hyperopia, the eyeball is too short and the object appears behind the retina. In this case, a positive lens (positive lens) is used to correct the vision problem.
Presbyopia is a common form of defective vision. With increasing age, the lens loses its elasticity; the eyes ability to focus on object near tends to decrease. A sharp near vision is therefore no longer possible without appropriate correction. Age related (far) sightedness (presbyopia) is not a disease but a normal, age-related loss of function.
Eye diseases are considered pathological changes in the organ of the eye. These changes can occur in isolation or infect the eye as part of systemic diseases (e.g. diabetes mellitus). Eye disorders are classified according to different aspects, e.g. according to the affected eye (e.g. diseases of the cornea, the retina, the eye chamber).
For more information about your eye or eye condition, please contact your professional Optometrist or Ophthalmologist.