Excimer laser is the most technologically advanced surgical tool to treat refractive errors that has revolutionized vision correction surgery. This remarkably precise ultraviolet laser creates invisible pulses of light that remove microscopic amounts of corneal tissue. Controlled by customized software, a computer calculates the number of laser shots required to achieve a patient's targeted refraction.
LASEK is a laser procedure used to correct short sightedness, long sightedness and astigmatism. It is relatively a new method that combines benefits of LASIK method and PRK method. The biggest advantage of this procedure is its non-invasive character without any incision made in the corneal tissue and its simple technique. It is an ideal procedure for people who have a cornea that is too thin or too flat.
The method of cutting the cornea with diamond knives has been used from 1970. LASIK method (laser in situ Keratomileusis), which was developed by professor Pallikaris in Crete, is one of many other surgical procedures used to correct refractive disorders. It is a modern excimer laser method. Historical roots of laser surgery LASIK go back to 1949 to Barraquer´s Keratomileusis based on which in 1966 Ruiz developed the method of automatic lamellar keratectomy (ALK). With the help of microkeratome he created a regular lamella on the surface of the cornea. Then after he uncovered it he performed second incision deeper into the stromal parts of the cornea which lead to desired flattening of the cornea.
The photorefractive keratectomy (PRK) is a laser procedure used to correct a low and intermediate short-sightedness and astigmatism. In some special cases it could be used also to correct a higher shortsightedness. The method of PRK refractive eye surgery was used for the first time in 1987 in Western Berlin. When correcting shortsightedness by laser we have to remove the central area of the stroma and this leads to a desired change in the incurvation of the cornea by photoablation with the help of excimer laser. This enables to focus the rays of light again on the retina. When correcting astigmatism, the laser balances irregular incurvation of the cornea by removing the tissue. The procedure is carried out only after the removal of epithelium of the cornea.
Many people suffer from sight related problems and certain refractive disorder is the most common cause of deteriorated vision. Nowadays, there are many ways of correcting such disorders. Today, wearing eyeglasses or contact lenses is very common. But try to imagine that you take part in some more active and more contact involving sport and suddenly wearing eyeglasses is not an option anymore.
Nowadays there are not any medications or eye drops which could eliminate cataract and improve vision. A surgical procedure is the only option for restoring vision. In this type of procedure opaque intraocular lens is removed and substituted by artificial lens.
Lazy eyes (amblyopia) does not belong to the category of refractive disorders but functional ones. We can define it as the decrease of the vision sharpness caused by slump in the inactivity of the human eye. The eyesight centre in the brain does not process the information coming from the handicapped eye but receives visual stimuli only from the second eye.
From the physiological point of view blindness can be defined as the state of sight deficiency. However, the definition, as it is applied to people who are legally classified as blind, is more complex. Total blindness is a permanent and complete loss of sight when the visually handicapped person cannot perceive the light. The significant decrease of vision functions is labeled as practical blindness.
It belongs to the category of eye diseases which manifest themselves by turbidity of eye lens. Cataracts of the eye is the most common cause of blindness and in 90% of all the cases it is a senile cataract. Sporadically, cataract originates as a side effect of the use of medications in the cases of diabetes mellitus or is congenital as a result of intrauterine infection. Sometimes it can originate from an eye injury, as a consequence of roentgen, ultrared or UV radiation, after long term use of medications such as cortisone and in the case of chronic inflammation of choroid. It can be also genetically conditioned.
Color vision disorder when the ability to percept color tones is disabled is known as color blindness. The name color blindness is usually not absolutely precise because the most of affected patients in not able to perceive only certain color what means that they have color vision to some extent. In the case of total color blindness they do not distinguish any color and perceive surrounding world only as black-and-white with different levels of brightness. Color blind people comprise not even 1% of the entire population and the rest can be labeled as color mistaken.