As someone who had LASIK years ago and only recently started wearing glasses again (thanks presbyopia!), I’ve had to learn about different types of lenses. Our Guest Geek post today breaks down the differences in five types of optical lenses to help you understand what kind of glasses you might need.
5 Types Of Optical Lenses
As the digital world keeps expanding, many of us find ourselves staring at a screen all day. With hours spent looking at something in such close range, we are finding a whole generation of people developing early eye conditions.
Shortsightedness is a rising concern for young people. However, as more of us develop the condition, better glasses are being made. You can even find Online Glasses Review websites to help you judge their quality and value.
But just because something looks good, doesn’t mean it’ll work for your eye condition. Knowing the 5 different types of optical lenses can help you learn which one best suits your needs.
Single Vision Lens
Single vision lenses only have one type of vision correction in the glass. They are the most common type of glasses and are often separated into “close vision”, “intermediate vision” and “distance vision” categories.
“Close vision” is designed for reading or writing. “Intermediate vision” is designed for viewing things at arm’s length, like a computer screen. And “distance vision” is for viewing far away, for example watching TV or driving.
If you saw glasses being sold in a non-medical store, you will notice the above categories separating them. However, your opticians will give you more specialized lenses for your eyes’ individual needs.
If you only have issues with your vision during specific tasks (such as using a computer or driving), then you may want to pick single vision lenses. They are cheaper than the other lens on this list because they only perform one sight-changing task. As you only need one area of your vision corrected, you don’t need to consider the other options.
Bifocals have a reputation for being large, clunky glasses that look horrible. That was true once upon a time, but designs have changed since the 80s and now these lenses can be just as sleek as their single-vision counterparts.
Bifocals are glasses that have two types of optical powers, the top two-thirds are for long-distance vision and the bottom third is for near vision (such as reading). Normally you will see an obvious line across the lens that separates the two glass types.
Before bifocal became popular, many people with multiple vision issues would only swap their glasses when they expected a lot of use as needed. For example, switching to their “reading glasses” when they grab a book or the “driving glasses” when they hit the road. For every day, they would pick one set that fit their needs the most.
Bifocals eliminate the need for two glasses, allowing people to see clearly without having to swap lenses every couple of minutes.
The glasses are designed to mimic our natural sight pattern. When we are reading, we tend to look down with our eyes, instead of our heads. When you look down with a bifocal lens, you switch from distance correction to near-sighted correction.
Originally invented in the 18th century, but gaining popularity in the 2000s, our technology has vastly changed since these glasses hit the market. Building from the benefits of the bifocal lens, two more glasses have emerged to make the lens change less starling.
Just as bifocals use two optical powers, trifocals use three. The top is still long distance, and the bottom is still near distance, but the middle is for intermediate correction. With these classes, you can have assistance while driving, reading, and also while watching TV.
These lens types aren’t needed as often as bifocals, however, they are a great benefit to those with multiple vision issues. For example, those with presbyopia are the most likely to use this lens type.
Presbyopia is when your close-up vision starts to deteriorate due to age. It tends to start when you reach 50 years old and continues to deteriorate as you grow.
The issue with trifocal and bifocal lenses is the dramatic cut between one lens type and another. It can be startling or even frustrating when you look down and see your vision has changed. To make sure you use the correct lens for the distance, you need to move your head as well as your eyes.
The second is known as the “image jump”. When you look at an object with both eyes and then cover one eye, the object will appear to move slightly. This is because our eyes don’t look at the exact same place when we view something. Instead, the slight gap allows us to create depth perception.
However, this depth perception is manipulated when you use lenses. For the most part, this wouldn’t be an issue, but when you switch from one lens to another, you’ll notice the object moves too.
Where bifocals and trifocals have hard lines where the lens changes dramatically, progressive lenses fade from one to the other. They can have two or three lens types to blend through, but you will not see a cut or line when you look up and down.
Many people prefer the natural gradient of power through the lens, as it won’t create the “image jump” issue nor will it create a jarring effect when you move your eyes.
However, as with everything, there will always be drawbacks. The first is that progressive lenses are expensive. The second is that you’ll have to train your eyes to know where the change from long distance to short distance is. It shouldn’t take long for the eyes to become adjusted, however for the first couple of weeks, you may find the process frustrating.
For people with vertigo, learning where the change is will help avoid nausea. You’ll have to balance the idea of a seamless gradient transition with a couple of weeks of off-balanceness.
Digital Protection Lens
Also known as blue light glasses, digital protection lenses are designed to help you reduce the amount of unnatural blue light entering your iris.
Blue light is shone on our eyes from computer screens, tablets, and smartphones. We also receive blue light from natural sources such as the sun. However, sunlight only hits us with a minimal amount of blue light, while our digital screens produce much more than our bodies can handle.
Blue light is one of the only types of light that can easily penetrate the eye. It can pass through our cornea and hit our retina, whereas most other colored light only reaches the cornea.
Because blue light can hit the back of our eyes like this, it can cause damage when we become over-exposed. Blue light glasses help dismiss a lot of the blue light while still allowing you to see your screens as normal.
This type of optical lens is still considered new technology, and so there aren’t many studies to prove or disprove their medical benefits yet. However many people who use this lens type say they are less prone to headaches, can look at their screens for a longer period of time, and can still see their screens without issue.
Before you purchase any optical lenses, you should first talk to your optician. Buying a trifocal lens may not be necessary, and if you don’t spend a lot of time reading then bifocals or progressives might not be needed either.
To know what type of lens makes sense for you, you’ll need to evaluate your lifestyle and your eyes’ needs.
Digital lenses don’t need an optician prescription, and you can easily buy them online. However, remember that they haven’t been scientifically proven or disproven yet.
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