Photo by César Couto
There is a good chance that you may have researched the various types of contact lenses (or contacts) that are available in the market. But it can be hard to figure out the right type of contact lenses for you and how to use them. Your eye doctor can help you to choose the right contacts for your eyes, but it’s still a good idea to know the types of contacts you can find on the market. Remember that contact lens technology is always advancing. This is the reason why you tend to find different, high-quality types of contacts.
Given the available options, the decision to switch from your glasses to find the right contact lenses may seem quite overwhelming. But it is easy when you put the options into categories. Understanding the different materials, wear times, and prescriptions can assist you to make an accurate decision. In this article, you will learn about the different types of contacts.
Types of contact lenses
The first type of contact lenses that were available on the market was the hard contact lenses. They were made up of either Plexiglass or PMMA. Before the discovery of PMMA, contact lenses were made using regular hard glass. Today, there are still few people who are using hard lenses, though they have poor oxygen flow. Besides, rigid gas permeable lenses tend to be more comfortable.
You can also find rigid gas permeable lenses (RGP), another type of hard contact lens. These are made up of flexible silicone and rigid plastic. You should note that these contacts allow more oxygen to pass to the eye. RGP contact lenses are usually smaller than soft contacts, covering only 75 per cent of the cornea. These contact lenses have replaced PMMA contact lenses.
It’s worth mentioning that in the 1960s, a new plastic known as a hydrogel was invented. This is a water-absorbing plastic that led to the manufacturing of the first soft contact lenses. In most cases, soft contacts cover the whole cornea and part of the sclera. These contact lenses are disposable, so they don’t last for a long period. You can wear soft contact lenses for between one day and one month.
Hydrogel contacts that you can find nowadays have between 40 and 80 per cent water. This hydrogel in the contacts can either be ionic or non-ionic. Quite often, non-ionic hydrogel soft contact lenses attract fewer proteins, meaning that there may not be buildup.
Some people get confused when it comes to daily wear and daily disposable contacts. You should remember that both are soft contact lenses, but they are different. You can wear daily-wear contact lenses every day for at least 18 hours. But you need to clean, sterilize, and store the contacts at night before you sleep.
Daily wear contact lenses have various lens replacement schedules. This includes weekly, bi-weekly, and monthly. On the other hand, daily disposable contact lenses last for single use only. You need to insert the contacts in the morning and throw them away before you sleep. This means that there are no storage or cleaning instructions since these contact lenses are not designed to be worn again.
You can also find extended-wear disposable contact lenses. These contacts are also considered to be soft contact lenses, but you need to wear them throughout the day and night for a certain period. You can find some extended-wear contact lenses that can last for up to thirty days while others last just for 7 days.
By now you may be wondering why you should use the daily contacts overnight instead of having extended wear contact lenses. This is because they have different oxygen levels. Daily contact lenses don’t offer adequate oxygen to the eyes to allow you to use them for 24 hours. If you decide to wear daily contacts for an extended period, you can develop some issues. This includes irritation, dryness, redness, itchiness, blurry vision, and swelling.
Extended-wear contact lenses are usually thinner and utilize silicone hydrogel. Remember that hydrogel is a more breathable material that allows adequate oxygen to pass through to your eye. Regardless of this, it’s not a good idea to wear extended-wear contact lenses for a longer period than recommended by your eye doctor. If you do, you can develop more serious issues like keratitis.
Contact lenses with corrective abilities
For many years, only people with simple prescriptions can wear contacts. With modern materials and technology, even people with complicated prescriptions can now wear specific types of contact lenses. For example, you can find spherical contacts that can treat nearsightedness or farsightedness.
You can also find toric contact lenses which are cylindrical and they are designed to correct heavy astigmatism. These contacts are often weighted so that they can be in place for vision correction.
People with age-related farsightedness which is called presbyopia can use multifocal or bifocal contact lenses. Each lens tends to have two or more powers to allow people who usually wear bifocals to see things clearly when they wear contacts.
There are also monovision contacts that allow each eye to function differently. The dominant eye can see things far away while the other eye can see things close up. In this way, your brain can learn to adjust to monovision, which is an alternative way of treating presbyopia.
You should note that most contact lenses have colored options. You can find contact lenses with visibility tint, so the lenses have a slight green or blue tint. The idea is not to change your eye’s color because the tint is usually not strong enough to do it. Instead, the tint assists you to see the contact lenses while placing them in and removing them. Also, it makes it easier for you to know the contact is in the case. It also makes it easier to locate your contact lens when it drops on the floor or counter.
There is also an enhancing tint on contact lenses. This means that the contact lenses have color, but you can still see-through. These lenses are there to improve your natural eye color. Therefore, if your eyes are light grey, then your eyes can have darker grey color when you use an enhancing tint. On the other hand, people with dark eyes cannot utilize this type of contact lens since they are not dark enough to alter their eye color.
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