Rigid gas-permeable contact lenses: reviews, manufacturing. Caring for hard contact lenses: a daily cleaner for rigid gas-permeable contact lenses
To date, there are many wayscorrection of vision. Very often to improve its sharpness, to eliminate other problems, contact lenses are used. Depending on the type of material, distinguish between soft and rigid gas-permeable contact lenses. Of course, the first type is most often used, however, the latter also has many advantages.
Materials for the manufacture of rigid lenses
Rigid lenses have become widespread inend of the twentieth century. Then the main material for their manufacture was polymethyl methacrylate. The lens itself had a relatively small size. The disadvantage of such lenses was the absence of gas exchange. The access of oxygen to the cornea was realized only due to the mobility and small size of such correction means. However, today more modern and qualitative materials are used. Rigid gas-permeable contact lenses are made of fluorine-silicone compounds. Due to this, the lenses have good oxygen permeability. It should be noted that they are quite comfortable, they are made individually, they produce an exact fit for a particular patient.
Indications for the use of hard lenses
Soft contact lenses have limitations inrange of optical power. Often they are prescribed for myopia to -12 diopters, myopia is not higher than 8 diopters. A stronger degree of myopia requires specific correction. Soft lenses with large optical power will be of considerable thickness in this case. This, in turn, increases the risk of complications (a tight fit can lead to eye hypoxia). You can, of course, use glasses, but today experts offer modern rigid gas-permeable contact lenses. They have a wide range of refraction - from -25 diopters to +25 units. The use of a modern material ensures a sufficient supply of oxygen to the eye. In this case, the thickness of such lenses is not much different from the corresponding parameters of soft products for correction of vision.
Design of a rigid lens
Modern hard lenses have an optical zone,which is located in the center of the product. Its diameter does not exceed 8 mm. Due to the sliding zone, which has a specific structure, the lens is securely fixed on the eyeball. The edge area has the smallest dimensions. It is she who is responsible for comfortable wearing of the product, ensures normal exchange of tear fluid under the lens.
The main advantages of these lenses
Many patients note that severegas-permeable rigid lenses are less prone to deformation, creasing. Due to the fact that their diameter is slightly smaller than that of soft lenses, such products leave an open peripheral area of the cornea. This, in turn, does not violate the process of tear-off. They are also more resistant to protein deposits, so the period of safe operation increases. Since the composition is completely free of water, the rigid lenses can not dry out, the patient does not need to use special moisturizing drops. It is also important to note their cost-effectiveness: only the change in visual acuity serves as an indication for replacement. With astigmatism, hard contact lenses are also shown. The patients' testimonies indicate that soft lens correction in this case is rather difficult, the only option is the use of rigid products. Orthokeratologic correction is also widespread. It involves the use of hard lenses only at night.
Orthokeratology. What is the essence of the methodology
This type of vision correction allows you to saveits sharpness in the daytime, at night it is necessary to wear special lenses. In the process of sleep, the cornea of the eye changes, its optical zone becomes flatter. This form is preserved all the following day. As a rule, the effect of this correction can last for two days. Night lenses are good for children, patients with a progressive form of myopia, in the presence of contraindications for an operation to restore vision. Also, this method is often chosen by people of certain professions: athletes, soldiers, builders, etc. Contraindications to orthokeratology therapy are diseases of the eye cornea, eyelids, all kinds of inflammatory processes, dry eye syndrome.
Negative moments in the use of hard lenses
In addition to the above advantages, rigid lenseshave their drawbacks. First of all, a certain period of adaptation is necessary (about a week). After getting used, discomfort disappears, but even a small break in wearing requires a new addiction to the products. There is some degree of deformation of the cornea, if rigid gas-permeable contact lenses were used. Patients' opinions suggest that the use of glasses after such lenses does not bring the desired result: the image becomes vague, the sharpness decreases. However, this is a temporary effect. After the restoration of the cornea, you can safely use glasses, without losing the quality of vision. Also, the process of selecting items is quite long, their original cost will also be an order of magnitude higher than that of soft lenses.
How to choose the gas-permeable lenses
In order to competently choose hard lenses,first of all it is necessary to contact a specialist. It determines the visual acuity, the maximum degree of correction. With the help of special equipment, the ophthalmologist measures the necessary parameters of the patient's cornea. Next is trying on a few pairs. All these manipulations are necessary for the perfect fitting of the lens. The production of rigid contact lenses is carried out individually, while more than 20 parameters of the eye are taken into account. The engineer models the required design (optical zone, slip zone, edge area). Next, on a special machine, the product is sharpened in full accordance with the layout. The most famous manufacturer in this field is the German company Wohlk. This manufacturer provides high quality products. As a rule, after 14 days you can get a complete set of lenses.
Daily care for hard contact lenses
First of all, any lenses require compliancerules of personal hygiene. Before removing or putting on hands should be washed with soap. Wipe them best with a waffle towel to avoid falling on the lens of various villi. Storage containers should be kept clean. For women, there are special rules. Makeup should be applied only after the lens is dressed. Accordingly, and remove it after removing the product from the eye. Also a daily cleaner is needed for rigid gas-permeable contact lenses. With its help, debris, tear fluid is removed. A deeper cleaning is carried out once a week. It is worth noting that you can not rub lenses very hard, so as not to disturb the optical properties. To date, a multifunctional cleaner for hard contact lenses is widely used. It allows efficient removal of protein deposits (for example, Boston Simplus solution), does not require additional enzymatic purification. It also perfectly disinfects and softens the contact lens. Over time, the product is more difficult to clean. In this case, the hard lenses can be polished in a special laboratory.
Special requirements for holders of rigid lenses
Wearing hard lenses impose certainresponsibilities for the patient. Visits to the ophthalmologist should be regular. This will enable the specialist to assess the condition of the eyes. At the slightest changes in the condition of the eyes, it is necessary to seek the advice of a specialist. Timely treatment will avoid such conditions as corneal edema, microbial keratitis, conjunctivitis, corneal ulcer, allergic reactions. Rigid gas-permeable contact lenses are an excellent tool for correcting vision in many cases, but they require correct and thorough care.