Types of Contact Lenses
There are two general categories of contact lenses – soft and rigid gas permeable (RGP).
Soft contact lenses are the most popular type of contact lens worldwide. Soft contact lenses can be used to correct various vision problems, including:
- Nearsightedness (myopia)
- Farsightedness (hyperopia)
- Blurred vision (astigmatism)
- Age-related loss of close-up vision (presbyopia)
Soft contact lenses conform to the shape of your eye. They’re comfortable and tend to stay in place well, so they’re a good choice if you participate in sports or lead an active lifestyle. Soft contact lenses are divided into daily disposable, weekly disposable, monthly disposable, extended wear and 3-6-month disposable lenses, depending on the duration of use.
Daily wear
Daily wear soft contact lenses are typically the least expensive option. You wear the lenses during the day, and remove them each night to be cleaned and disinfected. How long you can use a single pair of daily wear lenses varies depending on the manufacturer.
Extended wear
You can wear extended wear soft contact lenses while you sleep, but they must be removed for cleaning and disinfecting at least once a week. It’s still important to be cautious with overnight use, though, since it increases the risk of eye infections — even if the lenses have been approved for extended wear.
Disposable
Disposable soft contact lenses are generally the most expensive option. You wear the lenses during the day and remove them at night. They don’t need to be cleaned or disinfected. You simply use them for the recommended timeframe — such as daily, weekly or monthly — and then discard them. You might consider disposable lenses if you wear contacts only occasionally, you can’t tolerate disinfecting solution or you place a premium on convenience.
Cosmetic
Cosmetic or decorative contact lenses are colored contacts that change the appearance of your eye color, and in the case of circle lenses also make your iris appear bigger. Available in a broad range of prescriptions, so you can wear them daily or just for those special occasions.
Enhancement Tint
Enhancement tint is meant to enhance the existing color of your eyes. Usually best for people who have light colored eyes and want to make their eye color more intense.
Color/Opaque Tints
Colors or opaque tints are deeper tints that can dramatically change your eye color, even if you have dark colored eyes. Color contacts come in a wide variety of colors, including hazel, green, blue, violet, amethyst and gray.
Silicone Hydrogel
Silicone hydrogel lenses are the latest in contact lens technology. They create a balance of breathability and comfort for all day wear. Silicon Hydrogel lenses allow much more oxygen, than a traditional contact lens, to pass through the lens. This is essential for a healthy cornea.
Please note! When choosing lenses, it is important to know how high the oxygen transmission capacity (Dk/t) of the lens material is, because the contact lens forms a barrier that prevents oxygen from reaching the cornea of the eye. It is important to know that the higher the Dk/t value, the better. The higher the Dk/t value, the more oxygen reaches the cornea of the eye. The oxygen transmission capacity of conventional hydrogel contact lenses is significantly lower than that of silicone hydrogel lenses.
For example, 1-month hydrogel lenses:
Lens name Dk/t
Soflens 59 22
Proclear 52.3
For example, 1-month silicone hydrogel lenses:
Lens name Dk/t
AirOptix plus HydraGlyde 138
Biofinity 160
Contact lenses are further divided into spherical, toric and multifocal lenses according to the refractive error:
Spherical contact lenses are the most widely used and are used to correct myopia (- lenses) and hyperopia (+ lenses).
Toric contact lenses correct astigmatism and are intended for people who wear glasses with so-called cylindrical lenses.
Multifocal or progressive contact lenses are necessary for those whose near vision has deteriorated due to age-related changes. Like progressive glasses, multifocal contact lenses have an upper part for far vision, a lower part for near vision, and a middle part for intermediate distances.
Multifocal toric contact lenses are lenses that simultaneously correct astigmatism and presbyopia, or presbyopia. The prescription for such lenses has a sphere (sph), a cylinder (cyl) and also a reading add (add).