Toric lenses are a special type of optical product designed to correct the vision of people suffering from astigmatism. Such options are convenient and practical to use, and also have several advantages compared to traditional ones.
Features of astigmatism
Among all eye diseases, astigmatism has a special place. This is a problem that is associated with a defect in the shape of the cornea or lens, which leads to the fact that a person loses visual acuity and clarity. Most often, astigmatism appears at an early age and progresses in parallel with myopia or farsightedness.
Glasses or traditional hard and soft optical products can slightly correct this process in the presence of the initial form of pathology, however, the spherical shape of the lens cannot affect the problem if a person suffers from a disease of a higher degree. This option helps only in case of myopia or farsightedness. The solution to this problem is toric lenses. How to wear such options, the specialist will tell, since it is precisely on their position on the cornea that the person will clearly see.
The concept
Toric lenses - what is it? Such options have almost the same functions as conventional optical products, and are also made from the same materials. The difference lies in the shape of the lens itself, as well as in the position that it should occupy on the cornea in order to provide the desired effect. Thanks to this, it allows you to adjust astigmatism at a higher level, in comparison with traditional spherical optical devices and glasses.
There are soft and hard toric lenses. How to wear them depends on the type indicated. Soft lenses are more convenient in the selection, use and care, so most people prefer them. Despite this, the technology for manufacturing rigid optical products has changed in recent years, which has a positive effect on their level of comfort. In addition, they have a longer period of service, and are also perfect for correcting astigmatism, due to their strength and maintaining shape on the cornea. The choice depends on personal preferences, the severity of the vision problem, as well as on the individual characteristics of the person.
Features
Recently, the production technology of toric lenses has changed. This is characterized not only by materials, features of care and level of correction, but also by design. Today, specialized companies offer colored toric lenses, which, in addition to their optical function, also have a cosmetic effect.
Toric lenses are made of hydrogel and silicone-hydrogel, if we are talking about soft types, or from gas-permeable materials based on silicone, if we are talking about hard options. Of particular interest is the shape of the optical device. If traditional variants are usually spherical, then toric ones have the so-called spherocentric design, which allows more accurate astigmatism correction. Due to this, this option has two optical powers at the same time, which is the main advantage that toric lenses have. How to wear different options, a specialist will tell.
The difference between a spherical and toric lens
Spherical and toric lenses - what is it and what is the difference? The first types are responsible for the correction of myopia or hyperopia, then the second, due to their shape, simultaneously perform two optical functions. One indicator is designed 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 visual impairment. Only in this case will they fulfill all their functions. A spherical contact lens has a stable refractive power over its entire surface, so it does not matter what position it is on the cornea.
Benefits
Toric lenses have several advantages over traditional methods of vision correction.
- Due to their shape, they simultaneously perform two functions: correct vision and eliminate a defect in astigmatism.
- They provide an optimal position on the cornea due to the shape and additional βdevicesβ.
- Such options are suitable for those who suffer not only from astigmatism, but also from other corneal diseases.
- Such lenses can act as the lens of the eye if cataract surgery has been performed . For this, a special toric intraocular lens is used.
If a rigid type of optical products is used for vision correction, they have additional advantages, among which the following should be noted: a higher level of oxygen access to the cornea, accurate vision correction, the absence of the βdry eyeβ effect and resistance to protein deposits. Durability and a long period of use are also important advantages that hard toric lenses have. The price of such options is slightly higher than soft, and usually ranges from 300 to 3000 rubles.
disadvantages
Toric lenses have the same drawbacks as traditional soft or hard types. As for the first type of optical devices, this is primarily:
- relatively short period of use;
- difficult access of oxygen to the cornea, since a soft lens almost completely covers it;
- increased dryness of the eye, which sometimes requires the use of special drops or gel;
- the location on the lens of protein deposits from the eye, which can cause an allergic reaction, etc.
As for hard devices, the disadvantages are as follows:
- more complex and lengthy 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 type, cost is another disadvantage toric lenses have. The price of such options is much higher, regardless of whether they are soft or hard. This is due to the fact that they simultaneously struggle with the problems of myopia or hyperopia, and also eliminate the defect of astigmatism. In addition, special mechanisms are used to correctly position the lens on the cornea, which also affects the price.
How to choose?
Selection of toric lenses should be carried out by an experienced ophthalmologist, since two optical powers 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 has additional advantages. If a person prefers precisely the rigid form, then you need to remember that the product is selected under the cornea of ββthe eye, so after the diagnosis you need to wait until the rigid lens is made individually.
In addition to their optical functions, such options have a decorative effect. For these purposes, colored toric lenses can be used. They will allow not only to correct vision, but also to slightly change their appearance.
Fixation mechanisms
Unlike spherical, a 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 allow to achieve the effect of astigmatism correction, which toric lenses possess. How to wear a similar option will depend on the features of the mechanism of its fixation. There are several of them:
- Prismatic ballast. The presence of a slight thickening in the lower zone of the lens. Under the influence of gravity, the optical device goes into the correct position.
- Periballast. In this case, the lens has denser areas at the top and bottom, which are located under the eyelids. This allows you to keep her in the right position.
- Clipping. To do this, a certain part is cut off in the lower part of the lens, and with the help of 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.