Contact lenses are an innovation that millions take advantage of every day. For something so small, they have a massive impact on our vision! But, do you know how they work and how they help us achieve crisp, clear vision?
Contact lenses bend light so that it focuses on the retina, where the vision receptors gather information to send to the brain. This process is known as a refraction and glasses work in the same way. However, the difference is that contacts sit directly on the layer of tears which cover the eye and keep it moisturised. Since they stick to the fluid on the surface of the eye, they naturally move with your eyes.
A history of contacts
Contacts as we know them today first appeared in the 1970s, but the potential for them dates back to the 16th century where emerging theories of optics started to appear. It wasn’t until much later that the tools and materials necessary to create contacts were developed.
In 1971, the soft contact lens was introduced which transformed how contact lenses were used. Daily lenses were introduced in 1988, when disposable lenses were launched, but it wasn’t until 1996 that daily disposable lenses or ‘dailies’ came to the market.
Since the early 1990s, more and more people have turned to contact lenses to refocus their vision and reduce the need for glasses. There are various reasons why people choose contacts over glasses, such as leading an active lifestyle, cosmetic reasons or being able to tolerate weather changes without it impacting their vision. Today, we have silicone hydrogel lenses which are far more comfortable and can be worn for longer periods without discomfort or irritation.
Types of contact lenses
Contact lenses aren’t created equal - there are various forms that are suited to different purposes, from modality to how often you wear your lenses and the practicalities of that. Naturally, just as with glasses, contacts are also available in different strengths and thicknesses depending on your prescription.
Some lenses are also designed to suit different conditions. For example, toric lenses are weighted at the bottom of the lens which aims to correct astigmatism, while spherical lenses are suited to near and farsightedness. You can also purchase bifocal or multifocal lenses.
Dailies or extended wear?
Comfortable lenses are continually coming to the market, as materials evolve and manufacturers find more innovative ways to create lenses. But there are two distinct choices when it comes to choosing contact lenses – daily disposables and extended wear. As the name suggests, daily disposables are worn just once and then thrown away – so you can put them in in the morning, wear them throughout the day and then when you’re ready to go to bed, you simply take them out and throw them in the bin. They’re a hygienic solution and convenient, since there’s no maintenance. Extended wear lenses vary in terms of lifespan, but there are options for weekly, monthly or even some that can be worn for 30 days continuously including at night. They are convenient and cost-effective but there is a higher risk of eye infections since they require strict maintenance and hygienic cleaning to remain bacteria-free.
Putting in contact lenses and removing them
Getting started with contact lenses can take some getting used to – it’s an unusual feeling to touch your eye, after all! But once you get used to the process, you’ll realise that it’s incredibly easy and quick to do. There are just a few steps and you’ll be a contact lens convert in no time.
The first step is to wash your hands thoroughly with soap – this is to keep your lenses as clear of bacteria as possible and to prevent infections. Dry your hands with a dry, clean towel and then put a single contact lens on the tip of your index finger. Make sure that it’s not torn or inside out, and that if you have different prescription strengths for each eye, that it’s the right one for the eye you’re inserting it into.
Use one finger to hold your upper eyelid open and another to keep the lower lid open, then look up as you gently place the lens near your iris. Blink to make sure the lens sticks to the surface of your eye, directly over the pupil. To remove the lens, again wash your hands with soap and make sure your hands are fully dry before touching your eyes. Look up and pull your lower lid down gently with a single finger. Using your index finger, touch the bottom edge of the lens to gently slide it down off the iris, and apply slight pressure to squeeze the lens off your eye with your index finger and thumb. If you have daily lenses, you can now throw this lens away. If you have weekly or monthly lenses, you need to clean them and store them as per the manufacturer’s instructions.