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Thermal Scope Eye Damage: Can IR Optics Damage Your Eyes?  

L.p. Brezny | Updated June 1, 2023 | Why You Should Trust Us | How We Earn Money
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Using a thermal scope can help you hunt at night, so much so that you might rely on the scope more than your own eyes. However, because the thermal image is so much different than what your eyes are used to, that begs the question – can infrared optics damage your eyes?

Before attaching a thermal scope to your rifle, it helps to understand the potential dangers or setbacks you may experience. So, here’s everything you need to know about thermal scope eye damage.

Can a Thermal Scope Hurt Your Eyes?

The short answer is no; using a thermal scope won’t hurt your eyes. But the longer answer is a bit more complicated.

First, we need to define what “hurting” your eyes means. 

As a rule, there’s a significant difference between eye strain and eye damage. If you’re looking at screens all day, your eyes may feel sore or tired – an example of eye strain. Although repeated strains might be uncomfortable, they shouldn’t lead to permanent damage. (1)

Eye damage, however, can sometimes be permanent. In some cases, the damage may be degenerative, meaning it will get worse over time. If that happens, you may need surgery or corrective lenses to prevent further harmful side effects.

Fortunately, using a thermal scope shouldn’t cause strain or damage. However, if you’re using your scope for hours, your eyes may get tired, dried out, or sore. But, again, these are symptoms of eye strain, so resting your eyes will help them heal back to normal.

close up of the eye

Does the Color or Setting Make a Difference?

Most thermal scopes use red and yellow light to signify heat signatures and purple, blue, and black light to signify cold spots. If you’re using a night vision scope, it will use black and green coloration to help you see everything more clearly.

The color of the light hitting your eye can make a difference, so let’s break down these color settings. (2)

Red, Yellow, and Orange Light 

All light exists on a spectrum, with different colors coordinating with different wavelengths on the spectrum. Red light is toward the longer end, around 700 nanometers or so. 

Now, this kind of light doesn’t strain your eye very much, even with prolonged use. Sometimes, people with vision problems use red light therapy to help them see better.

Blue, Purple, and Black Light

Unfortunately, blue light has been shown to cause eye strain and, in some cases, mild eye damage. Part of the reason is that blue is one of the shortest wavelengths, so it has the most energy. While looking at blue light shouldn’t cause significant problems, it’s worse for your eyes than red light

Also, keep in mind that thermal scopes don’t necessarily project blue light – instead, that’s the color that shows on the infrared film.

Green Light

Green light wavelengths sit in the middle of the spectrum, so they don’t have as much energy as blue light but not as little as red. Overall, green light doesn’t impact your eyes much, so you can stare at a night vision screen without any adverse side effects.

Here’s a great video that runs through all the different color palettes of a thermal device:

More Reading: Thermal Scope Range

Much more eye strain will occur if you’re using the improper optic for the range at which you’re hunting at because the images will be much smaller in your reticle. So be sure to read more about the range of thermal scopes if you’re unsure what magnification is right for you.

Top Thermal optic for 300 Yards

If you’re already sure what range of scope you’re looking for, we suggest you take a look at our article on top thermal optic for 300 yards. We go over the best scopes not only at 300 yards, but long range scopes as well to make the perfect buying decision.


Are Thermal Scopes Dangerous?

No, thermal scopes are not dangerous. You shouldn’t worry too much about using these scopes because they don’t project visible light into your eyes. So, there should be no adverse reaction because nothing is shining into your eyes. 

What Effects Do Thermal Scopes Have on Your Eyes?

The only effects that thermal scopes have on your eyes is mild eye strain. This happens because the image isn’t as clear as what our eyes are used to seeing. Otherwise, there is no reason to believe that using a thermal scope will cause permanent eye damage, even if you use the scope regularly for hours.


  1. Mayo Clinic, Eyestrain, retrieved from www.mayoclinic.org/diseases-conditions/eyestrain/symptoms-causes/syc-20372397
  2. Scientific Research, Evaluating Infrared Thermal Image’s Colour Palettes in Hot Tropical Area, retrieved from https://www.scirp.org/journal/paperinformation.aspx?paperid=113082

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