Types of Contact Lenses

Wearing glasses and undergoing LASIK-surgery are some of the most common techniques of correcting vision. However, for people who do not want to use the above methods, contact lenses provide an excellent alternative. The use of contact lenses was first recognized in 1945 by the American Optometric Association. Currently, it is estimated that a staggering 125 million people rely on contact lenses to correct their visions globally. 

So, are you considering having contact lenses? There are numerous types of lenses that one can choose from. In most cases, contact lenses are defined by the material, designs, and features, and to some extent, formats. For instance, in 2019, the first light-adaptive contact lenses debuted in the U.S. Additionally, it is rumored that companies are working to produce contact lenses embedded with antibiotics. 

One should ensure that contact lenses are correctly prescribed.

Below are some of the types of contact lenses.

Contact lenses material

Material is one of the basics that define the type of contact lenses. There are numerous contact lenses under this category. 

1. Soft lenses: These type of contact lenses is made up of hydrogels. The lenses are characterized by very thin lenses and were formally introduced in the 1970s. They are the most prevalent type of contact lenses as they are naturally comfortable. Apart from hydrogel, other lenses are made of PMMA plastic. 

1. Silicone hydrogel lenses: These are usually advanced; however, they are more porous compared to the regular type of hydrogel lenses and allow more oxygen to get to the cornea. This type of contact lenses was introduced at the beginning of the 21st century and has become common among contact lenses wearers around the world.  

1. Gas permeable lenses: They are also referred to as GP or RGP. These lenses are characterized by rigid material, although they are super porous to allow oxygen into the eye. The porous nature allows them to be fitted closer to the eye compared to lenses made of PMMA. They are also credited with sharper focus compared to the afore-mentioned lenses. 

1. Hybrid lenses: These lenses are specifically designed to rival both soft and silicone hydrogel lenses in terms of comfort. They contain material from the other three types of contact lenses. In spite of all these features, only a small fraction of contact wearers use them. Their popularity or a lack thereof is attributed to the cost and difficulties while fitting.

1. PMMA lenses: These type of lenses are rigid and are made from a transparent and rigid plastic material. Although they have excellent optics, they are usually hard to fit and allow less oxygen into the eye. They are the least popular of all the contact lenses under the material category. 

Contact lenses wearing duration

Previously, contact lenses required the wearer to clean them on a daily basis. However, the trend was reversed by the introduction of more advanced contact lenses, which allowed people to sleep in them. Under this category, there are only two types of contact lenses available. 

1. Daily wear: this type of contact lens is designed to be worn only during the day. One should remove them before they sleep and ensure they clean them as advised. For example, they should be rubbed and rinsed and placed in the appropriate contact lens storage kit filled with the right solution to ensure they are disinfected. One should not sleep in them to lower cases of eye infections. 

2. Extended wear: As the name suggests, these types of contact lenses are the opposite of daily wear contact lenses. Unlike daily wear, they are available for overnight wear. The duration can range from one night and close to a month. Most of these are made of soft material and are highly porous. However, a few hard contact lenses have been approved for overnight sleep. Although these contact lenses have been approved for overnight use, one should ensure that they provide their eyes with adequate time to rest by removing the lenses from time to time. One should contact their eye care provider before considering this option, given that extended wear has been linked to numerous cases of eye infection. 

Replacement schedule

Most of the people who use soft contact lenses are usually required to replace their lenses from time to time. 

1. Daily disposable contact lenses: The term disposable, according to FDA definition, means discarding every time after use. This means that one should replace their contact lenses every day. Some people refer to these types of lenses as dailies. There is no need for one to invest in other products, such as solutions. However, one might find eye drops useful from time to time. They are appropriate for busy individuals, people who need to have lenses occasionally, and individuals suffering from allergy.  

2. Two weekly disposables: These types of lenses are worn only for two weeks before they are replaced. Occasionally, people refer to them as weekly wear lenses. Given the duration of wear, one is supposed to be clean and store overnight. As a result, one will require to purchase compatible contact lenses storage kit and other accessories. Although one should visit a professional to get the right solution, it is possible to do with a multi-purpose solution. These lenses are suitable for first-time wearers and people struggling with dry eyes. 

3. Monthly disposables: As the name suggests, their replacement schedule is one month. Like two weekly disposables, one should clean and store them overnight. They also require compatible cleaning solutions and appropriate storage kit. They are suitable for people who want to have their lenses on for a prolonged period and also for people who are conscious of long-term costs.

Orthokeratology (Ortho-K)

This is a type of procedure used to fit lenses. Usually, RGP lenses are fitted to help reshape the cornea in a bid to enhance focus on objects. The process is typically used to correct myopia. Overnight Ortho-K lenses are the most popular type of lenses. The vision correction using Ortho-K is temporary.