Every one of us wants to see the surrounding world in a clear and nuanced way, enjoying the quality of life provided by good vision. Often the wearing of contact lenses is the choice to ensure this. The origins of contact can be been associated with the 16th century, when Leonardo Da Vinci sketched out his idea of the way to correct the blurred vision. The first contact lenses were made much later - just after 300 years. They were made of glass, which was not a comfortable and safe material.

Nowadays, more than 125 million people around the world cannot imagine their everyday life without contact lenses. In order to ensure that contact lenses are safe to wear, everyone shall understand and follow the instructions for their use.

Rule 1–proper care for contact lenses, storage, insertion and removal – depending on the type of contact lenses, these rules may vary, but by the first purchase of the necessary contact lenses, they are always explained to the customer. After removing the contact lenses from the package, they should always be stored in the contact lens case only, noting the place provided for the lens of each eye. After each use, the contact lenses should be mechanically cleaned and rinsed with a disinfectant contact lens storage solution, then placed in a case until the next use. The contact lens storage case should always be cleaned and rinsed with a disinfectant contact lens storage solution. Case solution should be changed regularly. The purpose of disinfectant contact lens solution is to reduce the microbial concentration on the lens to a minimum. The usage period and conditions of storage of both contact lenses and solution must be observed, for example, they must not be left in the sun. Sun and heat create favorable conditions for bacterial growth, thus increasing the risk of infection in the eye. Personal hygiene should be observed when cleaning, inserting and removing contact lenses - wash hands thoroughly before handling with contact lenses. The aim of these rules is to reduce the risk of developing eye infection.

Rule 2 – proper wearing of contact lenses (CL). The contact lens wear regimen must be followed. Each contact lens has its own air permeability depending on its material and thickness (determined by diopters). Also, if the CL is worn longer than the prescribed time period, oxygen supply to the cornea decreases and corneal edema occurs (blurred vision, which can also be overlooked)that, under prolonged conditions, causes neovascularization of the cornea or the formation of newly developed blood vessels, ingrow into the periphery of cornea. That's why no one must sleep with CL inserted, because, during sleeping, also naturally i.e. without CL, the oxygen supply to cornea is already reduced. The duration of use of CL must be respected. When inserting the CL into the eye, it is perceived as a foreign object; when proteins from tears stuck to it, it becomes biocompatible to the human eye, but the longer time period CL is used, the more these deposits (including fat, dust, etc.) are formed, resulting in decrease of air permeability of the CL (the oxygen supply to cornea decreases), the lens absorbs less water and with this becomes less clear (vision began to blur). Over time, proteins on the lens denature (decompose) and the lens is perceived again as a foreign body – it began to annoy and causes discomfort.

Rule 3 – care for eye health. CLs are intended for healthy eyes. The supply of oxygen to the cornea (about 21% during the day) is provided by the tear film, while the CL breaks down the tear film and disassembles its normal structure, it becomes thinner, dries quickly, but the dry cornea and the lens cause discomfort and dry soft CL reduces air supply to the cornea, because the pores in it are blocked by the proteins mentioned above. Hence, care should be taken to moisturize the eye in a timely manner using artificial tears several times a day (if CL is inserted into the eye, the artificial tears should be applied that are intended for the use directly during the use of CL to avoid formation of sediment on CL; after the removal of CL, it is recommended to apply some of reepithelializing gels or creams that heal the micro-traumas occurred in the cornea by inserting and removing the CL from the eye). So, the CLs wearers belong to the risk group of dry eye syndrome; of course, if there are more risk-enhancing conditions or diseases that promote the development of dry eye syndrome (dry indoor air, conditioners, work with computer, thyroid diseases, etc.) occurrence of dry eye is inevitable, so it is important to moisturize it. Very marked dry eye syndrome and the use of CL may result in corneal epitheliopathy - or small defects of superficial corneal epithelium, staining at application of special dye - fluoresceine. In such cases, the symptoms of dry eye syndrome are usually marked and severe feeling of scratchiness, tearing may also be; this sometimes is dependent on patient's individual sensitivity. In such cases, the use of CL should be discontinued to avoid infection. So, the wearers of CLs with pronounced symptoms of dry eye syndrome (scratchiness, foreign body sensation, a pronounced feeling of sand, discomfort, tearing in the sun, wind, increased winking, eye redness) should visit the eye doctor.  No one must sleep with CL also because due to the pressure of the eyelid the CL is pressed more closely to the cornea during sleep, and often adheres to it, and, in these cases, the condition of the cornea deteriorates even more (it becomes very dry, epitheliopathy develops, or, in worse cases, keratitis or corneal inflammation). The healthy eyes with a good tear film are also the main prerequisites for using the night lenses (as a result of the use of special CLs during the night the corneal curvature changes and the application of vision correction means is not needed during the day). While the eyelids slide across the edges of the CL (at winging), the conjunctiva of the eyelids is irritated and causes chronic irritation and inflammation of the conjunctiva of the eyelids, which is presented as hyperaemia (redness) of eyelid mucosa, follicular reaction (uneven surface of the mucous membrane), which can cause a feeling of scratchiness. For these reasons, the CL should not be worn for too long and a rest should be given to the eyes more often, for example, on weekends if you are a permanent CLs wearer. In case of exacerbation of unpleasant symptoms, the eye doctor must be always visited, but the examination at eye doctor for CLs wearer without any complaints is recommended 1-2 times a year. 

Rule 4 – with CLs it is strictly forbidden: Swimming in water bodies (pools, lakes, rivers, seas, oceans). There are many dangerous micro-organisms living in the water bodies (for example, pseudomona aeruginosa, acanthaomeba) that enter the eye, behind the CL with water splashes, where they usually stay, as, due to CL, with the eye blinking the tear film fails to recover completely and, if the insertion and removal of the CL has resulted in small micro-traumas, which is usually the case, then there is both a place and a time to develop an infection. Sports activities in the beach. Firstly, when sand grains get into the eyes and behind the CL, they cause corneal erosion (the defect of the superficial corneal layer or epithelial defect), secondly, there are many microorganisms in the sand, including fungi, which are very dangerous in the case of the development of eye infection. It is also not advisable to carry out cleaning work in cellars, toilets and other places where fungi and other dangerous micro-organisms could potentially be present. 

If the bacterial infection is developed in the eye, it is very unpleasant (there may be feeling of scratchiness, eye pain, tearing, blurred vision, redness, sometimes discharge), but usually this can be treated relatively easy by the use of anti-bacterial medications. For example, the so-called CL keratitis is characterized by inflammatory punctate infiltrates of the cornea. If keratitis has not been treated timely, a deeper corneal defect may develop, even the corneal ulcer.

If the fungal infection has developed in the eye, the eye is relatively more relaxed (scratchiness, tearing is presented, but the eye often is less red and painless). Fungal keratitis is difficult to treat. Often it is difficult to differentiate biomicroscopically the bacterial keratitis from fungal keratitis and, in these cases, a bacteriological sample taken from a conjunctival sac or cornea is useful.  If fungal keratitis is suspected, an immediate anamnestic and biomicroscopic antifungal therapy is initiated locally in drops and / or intravenously, in more severe cases hospital treatment is required. In severe cases, with the development of an infection, an intrastromal infiltration (into the deeper layers of cornea) of the antifungal medication, the therapeutic keratoplasty or excision of the damaged fragment of cornea and replacement by a donor cornea can be applied.  If the process has gone too far and none of the above work, the more extensive surgical intervention is performed.

Contact lenses are strictly prohibited, if the eyes are irritated. 

In some cases of eye disease, CL is used for therapeutic purposes under the supervision of a doctor. 

Let's be cautious!