The human eye
The human eye is a highly developed sensory and visual organ which can absorb light stimuli and transmit it to the brain for processing. It enables us to perceive information where visible light is present, allowing us to orient ourselves in our environment. In addition to our spatial vision, visual acuity, field of vision, and the perception of colors are of great importance when considering the functions of the human eye.
As long as the axis length of the eye and its refractive power are balanced, the eye is considered to have ideal vision and does not need a visual correction (an emmetropic eye). With this ideal vision, incident light rays portray a sharp image on the retina.
Nearsightedness (also known as myopia) is a disproportion between the length of the eye and the refractive power of the eye’s optical system. If the eye has an extension of 1mm, this would correspond to about three dioptres of nearsightedness.
For a person experiencing nearsightedness, an image is already created in front of the retina, giving off a visual impression that is blurred. If, however, an object such as a book is being viewed at the correct distance from the eye (and also in the vicinity) a sharp image is created. As the name suggest, a nearsighted person can see things that are near, whereas things in the distance are blurred and out of focus.
With farsightedness (also known as hyperopia), the eye is too short in comparison to its refractive power. Cases of a lower refractive power of the eye are much rarer. When looking into the distance, the light rays fall almost parallel into the eye and would unite in the eye of a farsighted person only behind the retina to form an image.
Farsighted people keep the book as far away as possible in order to read the words clearly. During youthful years, objects can still be recognized well in the distance – a mechanism called accommodation. Over time, the elasticity of the eye’s lens diminishes causing the compensation of this mechanism to come to a standstill.
Corneal curvature (also known as astigmatism causing blurry vision) is a particular refractive error of the eye. The light rays emitted by an object in our field of vision are not bundled into a point along the retina, but are instead constructed into a focal line.
In detail, a ray of light enters the eye parallel to what is known as the optical axis. The light rays are then being refracted in varying degrees. As a rule, one plane of incidence can be determined with a maximum refractive power and one with a minimum refractive power. The difference between these two so-called main points is called the strength of astigmatism.
Age-related vision problems
An age-related visual problem (also known as presbyopia) is the progressive, age-related loss of the eye’s ability to adapt its near vision by means of a mechanism called accommodation. Seeing things sharply in the near vicinity is no longer possible without a suitable correction (e.g. reading glasses).
Presbyopia is not a disease. It is a normal, functional restriction that comes with age and becomes more noticeable from the age of 40. This leads to symptoms such as reading texts at a further distance in order to see clearly. Presbyopia does not influence an already existing visual disorder. It does, however, always require an additional correction for proximity.
Laser eye surgery
Correcting a visual disorder
The PRK is particularly suitable for patients with thin corneas, since no flap is formed for laser eye treatment. The method is therefore also popular with contact athletes, police and fire fighters.
Femto-LASIK is a particularly gentle eye laser procedure. Due to the formation of the flap, the method is particularly gentle and painless. You can see clearly on the next day.
EVO Visian ICL
The implantable contact lens is made of Collamer and is placed minimally invasively and invisibly behind your iris. The EVO Visian ICL is completely reversible and can be customized for your ametropia.