Toric lenses - how to dress? Lenses for correction of astigmatism
Toric lenses are a special kind of optical products designed to correct vision of people suffering from astigmatism. Such options are convenient and practical to use, and also have a number of advantages in comparison with traditional ones.
Features of astigmatism
Astigmatism is a special place among all eye diseases. This is a problem that is associated with a defect in the shape of the cornea or the lens, which leads to the fact that a person loses sharpness and clarity of vision. Most often, astigmatism appears at an early age and progresses in parallel with myopia or hyperopia.
Glasses or traditional hard and soft optical products can slightly correct this process in the presence of an initial form of pathology, however, the spherical shape of the lens can not affect the problem if a person suffers from a higher degree of disease. This option helps only in the case of myopia or hyperopia. The solution to this problem is toric lenses. How to dress these options, the expert will tell, since it depends on their position on the cornea depends on how clearly the person will see. Toric lens - what is it? Similar options have almost the same functions as conventional optical products, and are also made of the same materials. The difference lies in the shape of the lens itself, as well as in the position it should occupy on the cornea in order to provide the desired effect. It is thanks to this that it allows us to correct astigmatism at a higher level, in comparison with traditional spherical optical instruments and glasses.
There are soft and hard toric lenses. How to dress them depends on the type. Soft lenses are more convenient in selection, use and care, so most people prefer them. Despite this, the technology of manufacturing hard optical products has changed in recent years, which has positively affected the level of their comfort. In addition, they have a longer service life, and are also great for correcting astigmatism, due to their strength and keeping the shape on the cornea. The choice depends on personal preferences, the severity of the problem with vision, and also on the individual characteristics of the person.
The technology of toric lenses production has changed recently. This is characterized not only by materials, care features and level of correction, but also by design. To date, specialized companies offer color toric lenses, which, in addition to their optical function, also have a cosmetic effect.
Toric lenses are made of hydrogel and silicone hydrogel, when it comes to soft types, or from gas-permeable silicone-based materials, when it comes to hard variants. The shape of the optical device deserves special attention. If the traditional variants are usually spherical, the toric has a so-called spherocentric design, which allows more accurate correction of astigmatism. Due to this, such a variant has simultaneously two optical forces, which is the main advantage that toric lenses have. How to dress different options, the expert will tell.
Difference between spherical and toric lens
Spherical and toric lenses - what is it and what's the difference? The first types are responsible for correcting myopia or hyperopia, then the latter, due to their shape, simultaneously perform two optical functions. One indicator is intended to correct astigmatism for a particular meridian, while the other regulates visual acuity.
Toric lenses for astigmatism should occupy one position. Their meridians must strictly correspond to the position of the axes of the defect of vision. Only in this case they will perform all their functions. The spherical contact lens has a stable refractive force over its entire surface, so it does not matter in what position it is on the cornea.
Toric lenses have a number of advantages in comparison with traditional methods of vision correction.
- Due to its shape, they simultaneously perform two functions: correct vision and eliminate the defect of astigmatism.
- They provide an optimal position on the cornea due to the shape and additional "devices".
- Similar options are suitable for those who suffer not only from astigmatism, but also from others, get sick of the cornea.
- Such lenses can act as the lens of the eye in the event that an operation to remove cataracts has been performed. For this, a special toric intraocular lens is used.
If a hard type of optical products is used for vision correction, they have additional advantages, among which the following should be noted: higher level of oxygen access to the cornea, precise correction of vision, absence of the "dry eye" effect and resistance to protein deposits. Strength and long period of use are also important advantages that have hard toric lenses. The price of such options is slightly higher than soft, and usually ranges from 300 to 3000 rubles.
Toric lenses have the same drawbacks as traditional soft or hard types. As for the first type of optical instruments, this is primarily:
- for a relatively short period of use;
- hindered access of oxygen to the cornea, as the soft lens almost completely covers it;
- increased dry eye, which sometimes requires the use of special drops or gel;
- location on the lens of protein deposits from the eye, which can cause an allergic reaction, etc.
As for rigid devices, the disadvantages are as follows:
- more complex and long-lasting selection of toric lenses;
- low level of comfort and the need to adapt the cornea.
It is important to note one more point. Regardless of the type, cost is another disadvantage that toric lenses have. The price of such options is much higher, regardless of whether they are soft or tough. This is due to the fact that they simultaneously combat the problems of myopia or hyperopia, and also eliminate the defect of astigmatism. In addition, for the correct location of the lens on the cornea, special mechanisms are used, which also affects the price.
How to choose?
The selection of toric lenses should be carried out by an experienced ophthalmologist, since two optical forces must be taken into account. It is also important to determine the type - soft or hard. The first option is more comfortable, but the second one has additional advantages. If a person prefers a hard view, then you need to remember that the product is selected for the cornea of the eye, so after the diagnosis you need to wait until the rigid lens is made individually.
In addition to its optical functions, similar options have a decorative effect. Color toric lenses can be used for these purposes. They will not only allow you to correct your eyesight, but also change your appearance a little.
Mechanisms for fixing
Unlike a spherical lens, the toric lens will act as efficiently as possible only when it is correctly positioned. In this case, the action of the cylindrical component will be aimed at the optimal aspherical zone of the cornea. This will achieve the effect of correcting the astigmatism that toric lenses have. How to dress this option will depend on the features of the mechanism of its fixation. There are several of them:
- Prismatic ballast. The presence of a small thickening in the lower zone of the lens. Under the influence of gravity, the optical device moves to the correct position.
- Periballast. In this case, the lens has denser zones at the top and bottom, which are located under the eyelids. This allows you to hold it in the desired position.
- Clipping. To do this, a certain part is cut off at the bottom of the lens, and with this cut it is attached to the lower part of the eyelid.
To obtain the most accurate fixation, many manufacturers simultaneously use several of these methods.