Types of contact lenses

Contact lenses were more than a century ago. More precisely, in 1888, the first lens appeared that could be put on the eye and worn for several hours. It was invented and manufactured by the German physiologist Adolf Gaston Eugene Fick, calling it contact glasses.

Since then, the number of people who wear contact lenses has been on the rise. And this despite the fact that the first lenses were hard and not very comfortable: they were made of plexiglas. Ever since the invention of soft contact lenses in 1960, they have exploded in popularity. Although there is still an idea of ​​the discomfort while using them, but now this is no longer the case. However, new users have a lot of questions, so let's figure out what lenses are the best.

Classification of contact lenses

Contact lenses are divided into types according to the following parameters:

• Destination.
• Material.
• Wearing mode.
• Replacement period.

If you choose each of the parameters correctly, it will be more convenient to wear lenses than glasses. Modern lenses have many advantages, among them: high-quality vision correction, wearing comfort (subject to proper selection), flexibility of use. They do not distort the appearance, allow you to lead an active lifestyle and engage in many sports, including those that will not work practice with glasses. Let's look at the types of lenses in more detail.

Classification of contact lenses by purpose

Optical lenses

In fact, these are optical devices designed to correct impaired vision: myopia, hyperopia, astigmatism, presbyopia. Depending on the visual defect, they are designed to act on it, and all parameters work for this: both the shape and other properties.

• Spherical are used to correct myopia (nearsightedness) or hypermetropia (farsightedness).
• Toric are used to correct astigmatism.
• Multifocal (including bifocal) are used for presbyopia (the so-called age-related farsightedness that occurs in people over forty).

Cosmetic lenses

Their main purpose is to change or emphasize the natural color of the eye. In accordance with this, they are colored or tinted. At the same time, cosmetic lenses can either have optical power or not, that is, have zero diopters. If vision correction is not needed, but you want to “change” the color of your eyes, then you need to look at the latter. But people with visual impairments may also not refuse a cosmetic effect with simultaneous vision correction with their help, choosing the necessary optical parameters.

Types of contact lenses by materials

Soft contact lenses

These are modern lenses that are worn by a wide range of people with different visual problems. The many brands and types offered, the constant development of technology, the emergence of new, each time more and more advanced materials, have led to the fact that they are used more and more and cover almost all situations in which contact vision correction can be used. Ultimately, today they are most often referred to when they say “contact lenses” without clarification.

The main materials that are used for various types of soft lenses are hydrogel and silicone hydrogel.

• Hydrogel have a high moisture content, as well as increased smoothness, firmness and elasticity. They are very comfortable, and although they are used for short-term wear, they are very popular due to their high consumer properties.
• Silicone hydrogels are highly breathable – with them the eyes are well supplied with oxygen and keep their shape well. These properties allow you to wear them in prolonged mode without removing them for a longer time.

Rigid contact lenses

Historically, they were the first, but have remained in use today, acquiring new properties, and with them new advantages. Now hard contact lenses are made from modern materials. The former were gas-tight, modern ones have a very high gas permeability and in this respect are significantly superior to conventional soft ones.

Benefits of hard contact lenses

• Thanks to their clear geometry, unsurpassed visual acuity is ensured.
• Their smaller size provides better tear flow than soft contact lenses.
• Resistant to protein and fat deposits.
• Durability and long service life.
• Easy care.

Types of rigid lenses

• Gas-tight. This one is largely obsolete today thanks to modern, comfortable and breathable alternatives.
• Gas-permeable. The eye breathes in them in the same way as in silicone hydrogels, and much better than in hydrogels. They can be worn for a long time, in the process of wearing they do not dry out and do not change their optical parameters, or breathability, or moisture. This provides the best combination of wearing comfort and visual acuity.

Purpose of gas permeable rigid lenses

• Corrective. Used to correct high degrees of myopia (nearsightedness), hypermetropia (farsightedness) and astigmatism.
• Scleral, with increased diameter. Used to correct visual impairment such as keratoconus.
• Orthokeratology, also called night lenses. Used for night vision correction, which allows you to not wear glasses during the day. Prescribed by a doctor, not suitable for all visual impairments.

Types of contacts by wearing mode

• Daily wear. They are put on in the morning and taken off at night;
• Flexible to wear. You can sleep in them sometimes (1 – 2 nights);
• Extended wear. These lenses can be worn without removing up to 6 days in a row;
• Continuous wear. They are worn for up to 30 days without removing.

Types of contact lenses by replacement period

Traditional permanent wear contact lenses. The service life is from 6 months to 1 year. Produced in glass bottles.

Contact lenses for scheduled replacement. Available in blister packs – a special package that ensures the safety and sterility of the lenses.

• Planned replacement lenses. These are quarterly replacement lenses (three-month lenses).
• Frequent scheduled replacement lenses. Replacement once a month or more often (monthly or two-week lenses).
• Daily replacement contact lenses. Single-day use, which is worn once: put on in the morning and in the evening removed and thrown away.