Contact lenses are used by people for several reasons. For example, for aesthetic reasons – as a replacement for glasses. Also, contact lenses are useful where glasses cause difficulties and inconveniences. This can be everyday activities, sports, or some professions.
Also, contact lenses are recommended for people with a large difference in vision between their eyes. Among teenagers, carnival or colored lenses are popular, which can partially or completely change the color of the iris, as well as alter the appearance of the pupil and the shape of the eye itself.
In addition to standard corrective lenses, which have a spherical structure, there are several other types, which are described in detail on a specialized website. Bifocal lenses are specially designed for the correction of presbyopia, which is farsightedness that can develop with age. Orthokeratological lenses have an interesting principle of action. It is based on the fact that the lenses are worn all night and change the shape of the cornea during sleep. This allows you to go the entire next day without glasses or the lenses themselves. There are also toric contact lenses that correct astigmatism.
By manufacturing material, lenses can be divided into three types:
• Soft – the most popular today. Due to their high moisture content, they do not dry or tighten the eye, and it is comfortable to wear them all day. The material used is silicone-hydrogel polymers.
• Rigid – consist mainly of silicone; these lenses have the highest oxygen permeability.
• Rigid lenses made of organic glass – currently outdated and almost never used.
Unlike glasses, lenses require daily care and maintenance. The concept of care includes disinfection and cleaning after removing the lenses, as well as storage until the next use. A special solution and container help with this. Almost always the container comes with the solution, but it depends on the manufacturer.
According to wearing time, contact lenses are divided into three groups. These are daily lenses – used during the day and must be removed before sleeping at night. Extended wear – not removed for a whole week, but such lenses require special drops to maintain moisture levels. Continuous wear lenses can be used for up to 30 days, which is the maximum allowed time. Like extended wear, they require additional moisturizing with drops or a special solution.
Planned replacement of lenses is also important, otherwise they will cause discomfort, since the service life of lenses is limited. According to replacement schedule, lenses are divided into four categories:
• Daily – worn for one day, then disposed of.
• Frequent replacement lenses – such lenses are designed for two-week wear with removal at night.
• Planned replacement – these lenses have a wearing period of one month or more.
• Traditional – long service life, with proper care from six months or more.
For the first choice of lenses, it is worth consulting an ophthalmologist. The main purpose of lenses is to improve the quality of vision. Each person's eyes are unique, so when selecting lenses, attention should be paid to parameters such as base curve radius and diameter. This is necessary for comfortable lens wear. When choosing, the ophthalmologist will consider the wearing time of the lenses and the desired care method. The result will be an individual and comfortable optical system capable of improving the quality of vision.