Meta: Wondering if there’s a better way to deal with your eye problems? Here’s what you need to know about how toric contact lenses work.
Believe it or not, everyone has some degree of imperfection in their eyes. It’s true! But for many people, it’s so insignificant they never notice. For others, however, the imperfections are enough to impact their eyesight, causing blurriness at pretty much every distance.
For most of humanity’s history, people with these issues just had to deal with it--and it surely made life very difficult. Only in the last few centuries has the modern, scientific mind developed an answer for “astigmatisms,” the word for those little imperfections pretty much everybody has.
The most common way of dealing with astigmatism is by using bifocal glasses. These are simple tools--get them made and wear them! But a lot of people with astigmatisms don’t want to have to wear glasses, so they found an alternative: contact lenses.
Contact lenses are small lenses that actually fit the surface of your cornea--that is, the surface of your eye. There are two distinct types of contact lenses: the spherical type (the most common) and the toric type (not so much).
Most people know about the spherical kind of lens, but what about toric lenses? Here’s what you need to know.
What’s the Problem?
Toric contact lenses help with the common problem known as astigmatism. So, what is astigmatism, anyway?
Astigmatism is where the cornea or lens is misshapen so that light refracts poorly onto the retina. In other words, the window of your eyes is curved. Think of an old window that has warped over time, and how something you’re looking at through the glass is distorted. That’s what’s occurring in the eye.
Here’s an even more stark example: looking at an object in clear water, like a pool or lake. When you place a stick in water, it appears to bend. This appearance is because of the way the water refracts light. You see the image differently.
In the same way, an eye is wired to refract light within specific parameters so you can see clearly. If the cornea or lens is shaped out of alignment with each other or the retina, then the light coming into the eye doesn’t focus just right. The retina then perceives a blurred image.
The result of significant astigmatism is not just blurriness but also headaches and a general sense of annoyance. Things near or far are challenging to see, and you can lose your orientation. Although there are ways to cope without a fix like lenses or glasses, there are simple solutions thanks to modern inventions.
You may wonder what causes astigmatisms. The odd thing is that no one (so far!) has figured it out. It is typically hereditary, so it is passed on from parents to their children. But just because your parent has one doesn’t mean yours will be all that bad.
Astigmatism may change over time. It could get worse, or it could get better! It comes down to luck. For whatever reason, some people have slightly deformed corneas.
How Is it Tested?
So how is it tested? For an eye-doctor (also known as an optometrist) to diagnose you with significant astigmatism, you need to get a comprehensive eye exam. During these exams, you get tested for three different things: acuity, topography, and refraction.
Everyone is familiar with the acuity test: where you read letters from a specific distance until you can no longer read them. Testing your eye’s topography, on the other hand, may be less known. This is where the doctor gets a look at the specific curvature of the surface of your eye. This test will reveal any abnormalities that could be corrected artificially with glasses or lenses.
Finally, the eye doctor will test how well your eye refracts. The topography may check out, but by using a series of lenses on your eyes, the doctor may determine that you have some issues with refraction in your eye.
Altogether, this comprehensive exam should identify anyone with significant astigmatism. So if you’re having issues with your sight, it’s best to get checked out.
How Toric Contacts Work
So now that we know what exactly the problem is let’s talk about the solution. How do toric contacts work?
Most people have heard of contacts but don’t know there are two distinct kinds. For the most part, people probably expect contact lenses to be the same, conceptually, as glasses, just applied to your eyes instead of resting in front of them. That’s relatively true for what we can call normal contacts.
The typical kind of contact lens is roughly spherical in shape. Now, it is not actually a sphere--that would not be capable of being placed on your eye! By “spherical,” this means that the lens is actually shaped as if it were a slice of a sphere. Being shaped in this manner makes it pretty consistent in thickness and shape.
Normal contacts are usually soft (although they can be hard, too) and when they are placed on the eye, they can rotate when you blink and still work correctly. No matter what direction they have spun after you’ve put them in, the refractive quality of the lens will be the same.
These lenses are usually used for people with near- or far-sightedness (technically known as myopia and hyperopia, respectively), or people with minimal astigmatisms. Most people can get by with these lenses.
Toric contacts, rather than being spherical, are shaped like donuts. Yes, you read that right: instead of being slices of a sphere like standard contacts, toric contacts are slices of a donut-looking shape called a torus.
A torus is a highly technical shape that comes from geometry. In short, it’s the shape you get when a perfect sphere revolves around another sphere. It looks like a ring that is shaped like a tube. That all feels more complicated than just saying (as we did!) that it looks like a donut.
So toric contacts have very different characteristics because of this unusual shape. Instead of having a uniform refractive curvature (where each part of the lens focuses equally), there are different weights or thicknesses of parts of the lens.
The toric contacts work by having distinct focusing powers along the vertical and horizontal axes (or meridians, like with maps). These axes help correct the multifaceted issues of astigmatisms.
Toric contacts are distinct from spherical ones in another significant way. We mentioned that spherical contacts could spin around and around when you blink and that won’t affect their performance. That’s true. But for toric contacts, if that were to happen, you’d be super dizzy and would hate them!
A toric contact is designed to stay put on your eye and not to spin. It stays put because of those meridians--it’s like trying to use a map that is upside down. If it spins even 10 degrees out of sync, it will blur your eyes, and you’ll wonder why you spent the extra money on torics. Pretty significant difference!
Some toric contacts have special oxygenating power. It’s been noted that major astigmatisms usually receive a lot less oxygen. So a certain kind of toric called a silicone hydrogel (or SiHy) was invented to not only help with refraction but with oxygenation. Nice!
So that’s how toric contacts work, but how do you know when should you get them?
When To Get Toric Contacts (And When You Shouldn’t)
Because toric contacts are so strong, it is not necessary for all people with noticeable astigmatisms to get them. Most people are probably better off not getting them. The intensity of toric contacts makes it so if your eyes aren’t that bad, they’ll be negatively affected by the torics.
It has become more common for optometrists to recommend torics when they might not be needed. The clearest sign you don’t need them is that your eyesight has gotten worse. That doesn’t mean that if you need some time to adjust that you shouldn’t persevere a little. But most of the time, standard contacts should do (or just good ol’ glasses).
I Can See Clearly Now
It’s probably one of the coolest feelings to have one of your five senses corrected so it works right. But for many people, toric contacts just aren’t needed, even while most people have some degree of astigmatism. For others, it’s the perfect solution to their eyesight problems.
If you’re struggling to see clearly, it’s high time you get a comprehensive eye exam. Based on the results, you may be prescribed a trial run with toric contacts. Now you know some essential facs about these little guys, like that they are donut shaped and they can’t rotate on your eye. Hopefully, you understand how toric contacts work, and soon you’ll say, “I can see clearly!” Good luck.