Rigid gas-permeable lenses in many people are associated with those optical devices that were used a few years ago. They were difficult to wear and often caused redness in the eyes. However, technology has come a long way, and today's hard lenses offer a number of advantages over the more familiar soft options.
Concept and types
Contact lenses are small optical devices made of transparent materials that are used to correct vision, as well as to give an additional decorative and cosmetic effect. Compared to glasses, they provide clearer peripheral vision. In addition, lenses can correct diseases such as keratoconus and aniseikonia, which cannot be done with other methods.
There are several classifications of such optical products. They are divided into groups, depending on the material from which they aremanufactured, depending on the service life, frequency of replacement, design, degree of transparency, etc. In general, the following types are distinguished:
- soft;
- hard.
The first type is preferred by 90% of all contact lens wearers. Recently, however, thanks to new technologies, the second type is also gaining popularity. In the presence of severe myopia, as well as a high degree of astigmatism, hard contact lenses are the best option, because, due to their shape and density, they not only correct vision more accurately, but also prevent the progression of myopia. This is especially important for children and teenagers. Rigid lenses are also often preferred by older people as they are more durable and feel better when worn than soft lenses.
Features
Rigid gas-permeable lenses are made from special silicones and polymers that provide optimal optical strength, but at the same time, oxygen passes through them well. Most often they are used in situations where precise vision correction is needed, as well as to eliminate vision problems in especially difficult cases, such as astigmatism, keratoconus, orthokeratology, etc.
Given the features of this option, each lens must fit the person perfectly, so these products are made individually. In this case, the patient usually first comes to a specialist and is diagnosed, after which the optical devices themselves are made, and only then the doctor will be able to put them on. ProcedureFitting hard contact lenses takes longer than soft contact lenses because it requires individual calculations.
Technology
There are several features that rigid lenses have. The description of technologies allows to characterize it more precisely. Because many middle-aged people associate the term "hard lenses" with certain negative memories, the World Contact Lens Association has proposed that the term be dropped. Instead, the concept of "gas-permeable lenses" is proposed. The fact is that, despite the word "hard", this option differs from those lenses that were used earlier, since completely different methods are now used to make them.
Modern technologies make it possible to accurately correct the tear profile under the lens itself, as well as the thickening profile of the optical device. Particular attention is paid to the shape of the edges of the rigid part, as well as the main characteristics. For this, precise computer diagnostics, digital control of turning are used, and the highest quality and modern materials are used.
Benefits
Comparing rigid gas permeable contact lenses with traditional soft contact lenses, you can see a number of advantages that the former have.
- The cornea has no blood vessels, so it can only receive oxygen from the atmosphere. The soft optical lens completely covers it, which cuts off the oxygen supply. Modern rigid productsare made of special materials based on silicones and polymers, which have a high rate of gas permeability. That is why they allow more oxygen to pass through compared to thinner and softer options.
- Rigid hard contact lenses also provide the best possible visual acuity. Other correction methods do not give such a result. This is due to the fact that almost any cornea has certain irregularities. The soft lens follows the shape of the eye, including all its bulges and cavities. Rigid options create a perfectly flat optical surface. This allows you to carry out the correction as accurately as possible.
- These lenses do not dry out and do not need moisturizing.
- They have a longer service life due to their strength and hardness.
- Rigid gas permeable lenses are more resistant to the formation of various deposits that fall on them from the tear film. These proteins can serve as a source of allergies and also impair gas exchange.
While ease of use is a distinct advantage of soft optics, modern technology makes it possible to create a rigid lens that closely follows the shape of the cornea and is just as comfortable to use.
Flaws
Despite the advantages of rigid gas permeable lenses, some negative aspects of their use stand out.
- Such products require a longer period of adaptation and addiction.
- The price of similaroptions are much higher than soft ones.
- Requires special care solutions for gas permeable rigid lenses.
In addition, the process of selecting optical devices is quite complicated, since they are made individually for each eye.
Astigmatism
Rigid lenses are ideal for correcting astigmatism. Due to their strength and hardness, such variants hold and form a tear film on the anterior surface of the eye in the form of a sphere. An additional space is formed between the cornea and the back surface of the lens, which makes it possible to compensate for the manifestations of this vision defect.
Similar effect, however, is possible in the presence of a small degree of astigmatism. If the level is higher, then the possibility of correction with the help of spherical optical devices decreases. To do this, you can use parts of a different shape. The best option for this would be toric lenses.
Selection
Rigid gas-permeable lenses in Moscow are very popular, but the process of their selection is more complicated than for soft options. The optical product must almost perfectly fit the anterior surface of the human cornea. This can be checked with a special fluorescent type paint. That is why for the correct selection, you need to contact the appropriate doctor who will use special equipment.
Unlike himsoft, hard lenses require a period of adaptation. It usually takes 5-7 days, and in some cases more. Over time, the cornea of the eye adapts and wearer comfort increases significantly.
Many specialized companies are involved in the production of rigid lenses. The most famous are such giants as CIBA Vision (Switzerland), Vistakon (USA), Sauflon (UK), Cooper Vision (USA), Clearlab (UK), Zeiss (Germany), Baush & Lomb (multinational company), Avizor (Spain).), etc. Consumer feedback indicates that each option has its positive and negative sides, however, all corporations offer high-quality and reliable materials and a high level of efficiency and safety of finished products.
Care and regular follow-up
Rigid lenses provide high quality vision, but they also require more responsibility from the person. Firstly, they need to be properly and regularly looked after, and secondly, you need to visit an ophthalmologist often. Special attention should be paid to the safety rules for the use of hard contact lenses. This applies to the features of putting on and taking off, as well as hygiene rules.
Rigid gas permeable lenses are the best option for those who need accurate vision correction, as well as for those who suffer from astigmatism and other similar problems. Despite the fact that such products require more careful selection andslightly inferior to soft in terms of comfort, they have other undeniable advantages. Modern technologies make it possible to create options that will not only accurately perform all their functions, but will also be as convenient and comfortable as possible for a person.
