Contact lenses are a popular trend for those who find glasses a hassle or who don’t want to undergo laser surgery. Some people use it for cosmetic purposes – theatre, cosplay, or solely for a new appearance. Read on further to know the basics of contact lenses. However, don’t forget to consult an eye doctor before purchasing a pair.
Contact Lens Materials
In choosing a contact lens, choose one that will give provide you the satisfaction you need. The five types of contact lenses depend on the material they are made out of:
- Soft lenses are made from hydrogels – gel-like plastics that contain water. They are known to be very thin for it to conform to the shape of your eyes easily. Soft lenses were first designed in the early 1970s that immediately made them very popular because of how comfortable they were to wear. There were only two choices that time: the soft ones made from hydrogel and the hard lenses made of PMMA plastic. People had difficulty adapting to the latter because of how difficult they were to wear.
- Silicone hydrogel lenses are still under soft contact lenses but are more advanced. They are more porous than the regular ones, which allows more oxygen to enter the eyes and reach the cornea. These types of lenses were first made in 2002 and are now the most prescribed type of contacts in the United States.
- Gas permeable lenses, also known as GP or RGP lenses, are firm contact lenses that feel and appear like PMMA lenses. Unlike PMMA, however, they are porous, quickly allowing oxygen to pass through. Because of their porous nature, GP lenses have a closer eye fitting compare to those made from PMMA, making them more at ease to wear. Ever since gas permeable lenses were introduced in 1978, they immediately replaced the nonporous and hard PMMA ones. Additionally, GP contacts are also known to give off sharper vision compared to silicone and soft hydrogel lenses, especially for those with astigmatism. Although it may first take time for your eyes to adjust to GP lenses during your first wear, people mostly prefer these lenses after having tailored to them.
- Hybrid contact lenses are designed to give the ultimate comfort for the wearer that primarily rivals soft hydrogel lenses that are combined with the clear optics that gas permeable lenses provide. The center of hybrid lenses is rigid and gas permeable while being surrounded by hydrogel material. Despite its exciting features, only a handful are known to purchase hybrid lenses most probably because they have a more difficult fit and are also more costly to replace compared to hydrogel contacts.
- PMMA lenses are made from polymethyl methacrylate. PMMA is a plastic material that is rigid and transparent. It is also commonly used as a substitute for shatterproof glass and is mostly under the trademarks, Plexiglas, Perspex, and Lucite. As much as the PMMA lenses provide excellent optics, they still don’t allow oxygen to enter the eye, making them difficult for adaptation. Thus, they are now rarely prescribed and are currently replaced with GP lenses.
Contact Lens Wearing Time
Before 1979, people who continuously wear contact lenses habitually cleaned and removed them every night. Ever since the announcement of “extended wear” contacts, plenty of people started wearing them to sleep. Now, there are two categories of lenses regarding wearing time: daily and extended wear. Daily wear lenses should be removed every night, while extended wear contacts are allowed to be worn consecutively for seven days, even without removal.
According to the FDA, it was approved that there are contact lenses made for “continuous wear” that are allowed to put on for 30 consecutive nights at maximum.
Contact Lens Designs
Hydrogel and silicone hydrogel soft contact lenses have various designs that depend on the purpose intended.
- Nearsightedness (myopia) and farsightedness (hyperopia) use spherical lenses for vision correction. These lenses provide the same power throughout the whole optical area of the lens.
- Unlike spherical lenses, toric contacts provide different powers in various areas of the lens, mainly to correct astigmatism or either of the defects mentioned above.
- Multifocal contact lenses provide varied power zones for those who have far or nearsightedness to correct presbyopia. It is a condition where the elasticity of the lens loosens due to old age and eventually causes defective accommodation. Some multifocal lenses can also adjust astigmatism.
- Cosmetic contacts are known for their vibrant colors and are designed to intensify eye colors. Special-effect, Halloween, or theatrical contact lenses are also under cosmetic lenses. However, you will still need a prescription upon purchasing cosmetic contacts even if you don’t have any refractive eye errors in need of correction.
All the lenses mentioned above can be customized for eyes that are hard to fit. Fabricated lenses for special situations are also available for customization.
When to Replace Contact Lenses
Despite the appropriate care given, contact lenses – especially soft ones – are ideally replaced frequently to prevent lens deposit build-ups that can lead to contamination, increasing the risk of various eye infections. Soft lenses are categorized as to when they should be discarded.
Lens Replacement Frequency
- Daily disposable contacts – discard after wearing for 24 hours.
- Disposable contacts – discard after fourteen days or earlier.
- Frequent replacement contacts – throw after a month or every quarter.
- Traditional or reusable contacts – discard after six months.
If you prefer longer-lasting lenses, gas permeable ones are known to be less prone to lens deposits, therefore reducing the need for frequent discarding compared to soft lenses. Most of the time, GP lenses last a year or more before the need for replacement.
You are provided a sanitary solution in disinfecting your contact lenses. Follow the instructions written on the bottle on how to properly store and clean your contacts to avoid lens deposits.
Before you find a suitable lens for your eyes, you will have to go through the process of trial and error. That is why it is vital to visit an eye care professional first before deciding on getting a proper pair of contact lenses. Remember always to follow the necessary precautions to avoid unwanted risks. Check out TTDEYE for more eye care tips!
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