Which contact lenses are right for me?
Contact lenses are small plastic cups that float on the tear fluid of the eye. Compared to glasses, they have many advantages: they are invisible and therefore do not change the look, the field of vision is not disturbed by a spectacle frame, they do not fog up and they are not in the way during sports. Nevertheless, in Germany only 40 million eyeglass wearers have 3.4 million contact lens wearers, of which only half use the contact lenses regularly. Why is that?
Contact lens wearers often complain about the poor compatibility of their lenses. Most of the problems are due to one of these issues: infrequent replacement, incorrect or missing adjustment, poor hygiene or prolonged wear. So mostly causes that can be corrected or avoided in advance. A fundamentally bad idea when buying contact lenses are cheap offers from the drugstore or from the internet. The contact lens must fit the eye - if it does, only a contact lens specialist can judge. The most common contact lens types at a glance:
Hard (dimensionally stable) contact lenses
Advantages: Hard contact lenses with a diameter of 8 to 10 millimeters are smaller than soft lenses and swim relatively loosely on the tear film. They hardly absorb tears. The eye is constantly supplied with oxygen and the tear fluid under the lens replaced regularly. People with dry eyes often tolerate hard contact lenses better than classic soft lenses.
Disadvantage: Hard contact lenses do not adapt so flexibly to the eye. This gives it a foreign body sensation when blinking and it takes a little longer to get used to the lenses. The adaptation of hard contact lenses is therefore more time consuming. Because of the smaller footprint they can slip and even get lost, and foreign objects such as dust can get under the lens. That hurts then.
Suitable for: People with rather dry eyes, who can get used to the foreign body sensation well and for people, where certain visual defects such as corneal irregularities must be corrected.
Soft hydrogel contact lenses
Advantages: You get used to soft contact lenses quickly. They are made of flexible material and adapt to the ocular surface. Even with sensitive people, the feeling of wearing is usually pleasant. Soft contact lenses are larger than hard, their diameter is 12 to 16 millimeters. As a result, they sit more stable and slip less. With soft contact lenses, almost all refractive errors, including astigmatism, can be corrected.
Disadvantage: Conventional soft contact lenses are usually less permeable to oxygen than hard ones. The exchange of tear fluid under the lens is reduced and the lenses absorb tear fluid. This can dry out the eye additionally. Soft lenses made of modern materials such as silicone hydrogel can be an alternative in rather dry eyes.
Suitable for: Contact lens beginners, people with stable tear film.
Soft silicone hydrogel lenses
Advantages: Silicone hydrogel lenses have been around since the late '90s. These modern soft lenses allow up to three times more oxygen than conventional hydrogel lenses and can easily be worn for 16 to 18 hours at a time. Special day and night lenses made of silicone hydrogel can be used continuously for up to a month - even at night. Handy for long nights or traveling.
Disadvantage: Silicone hydrogel lenses are more dimensionally stable than conventional soft lenses. This makes it easier for the eye to mechanically irritate the eye. To prevent this, the proportion of silicone in newer lenses has already been reduced again - at the expense of oxygen permeability. Silicone hydrogel lenses are slightly more expensive than other lenses. In the case of the day and night lenses, the nocturnal wearing according to the recommendations of the "Kuratorium Gut See" should be limited to exceptional cases such as travel and agreed with the contact lens specialist. The reason: The risk of infection is about five times higher at night than during the day, since the flow of tears is missing and germs can not be flushed out.
Suitable for: Anyone who wants to wear their lenses longer during the day, or even overnight in exceptional cases, as well as for those who are looking for a lens that allows more oxygen to the eye.
Replacement contact lenses (daily, weekly and monthly lenses)
Advantages: Replacement contact lenses are soft lenses that are only worn for a period of time and then replaced with new lenses. The period ranges from one day to six months. They are now more common than the usual soft one-year-old lenses. Since they are thinner than annual lenses, they let more oxygen through.The shorter the intervals at which the lenses are replaced, the less likely will be deposits on the contact lenses. As with all soft contact lenses, you get used to them quickly. Those who rarely wear contact lenses - for sports or going out - or want to save time and costs for care, can use daily lenses. Other Benefits: Short-term vision changes can be accommodated with replacement lenses and loss of lens is not so expensive.
Disadvantage: Replacement lenses can not correct all refractive errors. Due to standardized diameters and radii, they are also not suitable for every eye.
Suitable for: Daytime lenses are suitable for anyone who only occasionally wear contact lenses and / or shy away from the time-consuming care. Weekly and monthly lenses are a hygienic alternative for those who do not need custom lenses.
night lenses
Advantages: Night lenses (Ortho Keratology lenses or Ortho K lenses for short) are worn at night. The hard, extremely oxygen-permeable lenses model the cornea so that the wearer can see clearly during the day. No visual aid is needed during the day. Studded eyewear or the problem with limited wear on contact lenses are a thing of the past. Unlike laser corneal surgery, there is no scarring on the cornea and corneal deformation is reversible. Disadvantage: Until the vision correction is stable, you have to wear the night lenses for one to two weeks. The change is not permanent. As soon as you stop using the night-lentils, you start to get worse. Nightlenses may only be adapted by specially trained contact lens specialists. The total cost is relatively high and not everyone can handle the foreign body sensation at night.
Suitable for: Anyone who does not want to wear glasses or contact lenses during the day and who is looking for an alternative to surgical correction of ametropia.
Contact lenses for presbyopia
The presbyopic vision is added to the existing visual impairment at least 45 years. With presbyopia the Nahsehschärfe decreases. If an existing myopia has to be corrected at the same time, there are the following possibilities - analogous to the glasses:
a) Monovision systems
Advantages: Monovision systems correct one eye for proximity, the other for the distance. The method is inexpensive and has been widely used in the past to correct presbyopia.
Disadvantage: The spatial vision and the contrast perception worsen. As a result, distances can not be estimated as well, for example when pouring drinks or driving a car.
Suitable for: People who do not drive and who come to terms with the deteriorated spatial vision.
b) multi-intensity lenses (progressive lenses)
Advantages: You can clearly separate the near and far range with multi-intensity lenses. Most are corrected above for the distance and below for the proximity, similar to a bifocals. Alternatively, you can arrange both areas of vision in the center of the lens and then look through the near and far areas at the same time. Using the brain's ability to focus on the sharp image and fade out the blurred image.
Disadvantage: Usually, lenses move on the tear film. To keep the bifocal lenses in place, they are heavier at the bottom than at the top. A very good fit is crucial for all multi-intensity lenses. In addition, the brain takes a while to get used to it. As with progressive lenses, it can lead to blurred vision in the corresponding contact lenses in areas.
Suitable for: People who are looking for an alternative to glasses even in old age.
