Johannes
August 13,2021
6 min read

Can I Wear Contact Lenses In A Sauna? The Scientific Answer...

Yes You Can, But, Here's Why Perhaps You Shouldn't!

*Disclaimer: The written article is based on a summary of existing literature on the topic of infrared saunas. The article is for educational purposes and the information provided below cannot be taken as a promise to help with acute health problems or diseases.

The claims in the article are backed by 21 scientific references. All references are numbered. You can access the text of the reference by clicking on the number.

Here's a question I'm getting very often: "Can I wear contact lenses in a sauna?" or "can you wear contact lenses in a sauna?" This blog post will consider that topic. The question is closely related to an earlier blog post I wrote, "How Hot Is A Sauna?" and "What To Wear In A Sauna" I briefly considered the topics of contact lenses and heat there but I'll go into more detail in this blog post.

The short answer to the question is "you can but it's probably best not to.". Here's how I justify my decision - let's start with defining the problem of contact lenses:

Wearing Contact Lenses In Sauna & The Problem Of High Heat

If you want to explain any scientific topic, it's always smart to best to break that topic down. So here's where I'm coming from, with regard to the heating of lenses, when regarding different sauna temperatures:

  • Dry saunas with low humidity reach temperatures of 80-90 degrees Celsius at the maximum (176-194F).
  • Finnish saunas commonly have maximum temperatures of 90-100 degrees Celsius (194-212F) (1).
  • Infrared saunas - the ones we're specialising in at Clearlight Infrared Saunas International® - have maximum temperatures of 55-60 degrees Celsius (131-140F) (2; 3). For that reason, it's probably a better option all-around.

Why does heat matter? Simple: that higher air temperature translates into increased heating of your contact lenses. 

But there's more to the story: in case of the infrared sauna, the infrared light is absorbed by objects in their environment, increasing their temperature from the inside out, affecting all chemicals in the lens.

Hence, you can imagine that if your contact lenses are heated up together with your surroundings. As a result, here's a problem that commonly occurs:

Drying Out Contact Lenses In Saunas

Different lenses exist which are made out of different materials (4). Regarding the different materials making up different lenses, one study from 2019 states:

"Contact lens materials are typically based on polymer- or silicone-hydrogel, with additional manufacturing technologies employed to produce the final lens." (5)

Next up, there's also a difference between more soft and more rigid lenses, with hybrid versions as an intermediary option between soft and rigid (6). I'll come back to that hybrid option soon. 

Why pick soft or rigid? Well, in general, the eyes more easily adapt to the softer lenses but over time these can also increase discomfort over more rigid models. Rigid models are thus most safe with regard to eye health, for now, but less comfortable to adapt to than softer options.

Let's explore some more and begin with considering the softer version:

Soft Lenses In A Sauna

Many lens wearers prefer soft lenses because they are comfortable...

And yet, here's an issue:

Softer lenses contain more water, which theoretically should increase their susceptibility to be affected by infrared light. Why? Well, different types of infrared light are absorbed by water to different extents. Without overcomplicating too much, the far-infrared wavelengths included in our Clearlight Infrared Saunas International® will certainly affect the water in the soft lenses (7; 8; 9).

Why does water inside a lens matter?

Well, to put it simpler, the infrared rays from your sauna will inevitably heat up the water in a soft lens. Remember that soft lenses have a very high water content. As a result, you'll heat up an object that's directly located on top of one of your organs: your own eyes. Also, because of the high water content of especially soft lenses, the lenses are more likely to dry out.

No bueno...

Here's why:

By drying out, soft lenses will contain less water content. Less water content, in turn, lowers the ability of oxygen to penetrate the lens. And increased oxygenation of the eyes is one of the main reasons why people opt for soft lenses in the first place! Also, the soft lens might dry out permanently.

Also, that heating effect of infrared is not frequently talked about regarding eye health, and yet, could theoretically overheat parts of your eye and damage it if you're wearing a lens. 

Here's why:

Just imagine getting some overheating hot gel on your skin: burning wounds are not out of the question in such a case or damage due to prolonged overheating. And yet, with a gel-like soft lens placed directly on their eyes, many people regularly spend time in a sauna, without worrying about the side effects.

Also, more specifically, the heating from dry saunas and Finnish saunas could also alter both the temperature and oxygen exchange with regard to soft lenses. 

While different in dynamic than infrared light exposure, I still do not recommend it because it is more likely to lead to localised overheating compared to if you don't wear anything. 

My recommendation? Play it safe! If you can enjoy an infrared sauna without lenses, do so. There's a reason why, and I'll demonstrate below:

Next up, let's consider hard lenses:

"Harder" Or Rigid Lenses In A Sauna

Rigid lenses traditionally didn't allow for good oxygenation of your eyes. Over time, however, that problem became less severe with technological advances. In some eye conditions such as "keratoconus" and "astigmatism", hard lenses generally work better, although soft opens are closing in on that technological and practical advantage (10; 11). 

In general, rigid lenses are more "chemically inert", as opposed to soft lenses which have at least 40% water and sometimes over 60% (12; 13). Fluor, silicone, and acryls are the main components of these hard lenses. The simplest way to imagine those materials is that they are combined into a glassy material.

The good news? In general, the thermal conductivity of silica and acryls are much lower than that of water (14). Energy absorption of infrared light is generally also going to be lower than that of water, so there's less of a problem here. Also, these lenses contain less water, so a high-humidity high-heat sauna such as the Finnish one will be less damaging also.

Put in plain English, all materials of rigid lenses are less likely to be affected by all types of saunas. But that's not all:

Perhaps a more important issue is that contact lenses might release microplastics - especially under higher temperatures (15; 16; 17; 18).  That mechanism is somewhat speculative though.

For now, and for optimal eye health, I'd avoid also heating your rigid lenses to a high temperature. That statement is especially true as the toxins may be released near your eyes.

Next, up, one more type of lens:


Hybrid Lenses

Hybrid lenses only make up a small portion of the lens market. Hybrid lenses contain some parts of rigid material and some parts of soft material. Hence, both situations I just laid out are applicable to this lens.

I can thus keep my message short: you'll be exposed to the potential downsides of rigid and soft lenses. There's a bit less risk of drying out than soft lenses, and a bit less risk of microplastic release of hard lenses, but both are present.

No need to explain much more than I already have...

So what's one solution? Here is one:


Disposable Lenses As A Solution?

Let's say you're regularly spending time with friends in a sauna and you don't want to give them up. In such a case I'd recommend using disposable lenses, and not your regular ones. 

If you dry out or damage disposable lenses, you'll at least save your lenses for daytime wear. The downside is that you still end up with localised (over)heating of tissues near your eyes and potentially releasing toxins. 

So, if you can let go of the idea of having to see perfectly in a sauna, and can become comfortable seeing the silhouette of your friends instead of their full complexion, that's an even better option than disposable lenses. And yet, I also know that people want to see when their friends are around. As often, this medical choice comes down to personal experience. There is no easy way out, here.

And, lastly, there's one more problem with all of these aforementioned lenses:

Bacterial Buildup

There's another issue with wearing lenses in a sauna: 

You'll increase your risk of "Acanthamoeba Keratitis", caused by a single-celled organism (protozoa) (19; 20; 21). These protozoa live almost everywhere, such as in the soil, water, and air. 

An increase in humidity and/or hot water exposure can increase your risk of your eyes getting infected if you're wearing lenses. 

Improper cleaning of the lenses, and using them in a bath, are the main risk factors for this condition. Of course, sauna use is right up there, although unproven right now. Nevertheless, it's not impossible that heat and humidity increase that risk. For that reason, if you do enter a sauna with contact lenses, make sure you clean and disinfect very well before and afterwards! Also, avoid rubbing your eyes and lenses, especially during your sauna sessions.

I repeat: keep hygiene in optimal regard. And, now that I've laid my viewpoint bare, let's conclude:

Finishing Thoughts: Are Contact Lenses Safe In Sauna?

My final answer?

You won't like what I have to say but here's the deal:

Currently, there's no available direct high-quality research - such as "randomized placebo-controlled trials" - comparing eye health with and without contact lenses in a sauna. The answer I'm giving you in this blog post is based upon reasonable expectations of what happens with different lens materials such as water, acryl, fluor, and other materials and their combinations.

And yet, based upon that physics background, it can reasonably be expected that something happens when you heat these materials up and the end result is unexpected. Also, it's reasonable to expect lenses to affect eye health if you wear them in the sauna frequently. 

What I would like to see is more medical research on the topic so that there's more certainty regarding the extent of the potential eye damage. Many factors almost certainly come into play whether damage occurs if you wear contact lenses in a sauna and the extent of the damage. 

My recommendation? You better be safe than sorry!

And there's one more argument I can make in favour of my case: In medicine, there's a solid consensus that wearing contact lenses during sauna use is not recommended. So if you ask your family physician or ophthalmologist, they'll tell you not to wear contact lenses in a sauna - I just gave you some likely reasons why they're right!

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