What are the different types of contact lenses?
Contact lenses are a popular choice for many people who have problems with their vision. However, it can be a daunting task deciding on the right types of lenses when there are so many different products on the market.'Soft' and 'hard' contact lenses are the two main categories of lenses, but there are still a number of different options within these groups. This list of the most common types of lenses should help you decide which available products are the best for you and your eyes.
Soft contact lenses
Soft contact lenses are the most popular option worldwide. They are made from soft, flexible plastics that allow oxygen to pass to the eyes and have daily replaceable and extended-wear versions.The benefits of soft contact lenses include a very short adaptation period, which means they are comfortable to wear almost immediately. They are also difficult to dislodge and great for active lifestyles.Water content in lenses.
Water content is an important feature in soft contact lenses. Generally, the higher the water content of the lens, the more oxygen can pass through its surface.This helps with comfort levels and also maintains optimum eye health. The downside is that high water content lenses are sometimes more fragile, so may tear with frequent handling. However, if you have silicone hydrogel lenses, water content is likely to be less of a concern. This is because the relationship between water content and oxygen permeation in these lenses is different, and silicon hydrogel can still transmit high levels of oxygen irrespective of water percentage.
Hard contact lenses
Hard contact lenses - or rigid gas permeable (RPG) lenses - are made from durable plastic and they allow the efficient transfer of oxygen to the eye. Due to their rigidity, they can tend to offer sharper improvements to vision than soft lenses. RPG lenses also tend to help with a wider array of vision problems.They are fairly durable, which can make them a more cost-effective option than other alternatives. However, they must be worn regularly to remain comfortable and are more easily dislodged than soft contact lenses. RPG lenses are smaller than soft lenses and are designed to move around on the eye. This means there is a greater chance of dust and debris getting caught beneath the lens.
RGP lenses also have a longer initial adaptation period compared to soft contact lenses.Single vision lensesSingle vision lenses have one prescription across the entire lens. This means they are usually designed to improve vision for a specific task, this is most common in the long range or for correcting distance vision problems.In some instances, people may be prescribed a different single vision lenses for each eye. One will be for distance vision and the other for near vision.This is a monovision solution and is a less common approach to treating presbyopia. Toric lensesToric lenses are contact lenses that are shaped in a specific way to help with astigmatism. Astigmatism is a minor eye condition which causes blurred and distorted vision, but may also lead to headaches and eye-strain if left untreated.A toric shape is a geometric shape that is similar to a donut, and toric lenses are shaped like a slice from the side of that donut. In contrast, single vision contact lenses are shaped more like a slice from the side of a beach ball.Toric lenses create different focusing powers on vertical and horizontal orientations, helping to correct the vision problems associated with a curved cornea or eye lens that people with astigmatism suffer from. It is particularly important to have toric lenses fitted properly, as they must sit on the eye in a certain way.
Multifocal lenses are the modern solution to monovision contact lenses. Multifocal lenses have different prescriptions that can help with a range of vision problems including problems with near and distance vision. Multifocal contact lenses may also be referred to as varifocal or progressive lenses.There are different types of multifocal contact lenses that can help improve vision at distance and near. A common design is the concentric multifocal lenses.
The centre of this type of lens has the normal vision prescription, while the outer ring helps with near vision. In some instances it can be designed the other way around, depending on your prescription and how you use your eyes. While multifocal contact lenses usually offer better visual acuity for different distances, they tend to be more expensive due to their sophisticated design. Some people may also find it difficult to adjust to the viewing experience of multifocal lenses if they have previously used other types.To find a suitable contact lens for your prescription and your lifestyle, it is best to visit your optometrist.