VLT in Sunglasses

Uncover the Power of Visual Light Transmission in Fishing Sunglasses

It doesn’t take long for fly anglers to realize the importance of high-quality sunglasses. One look at a clear stream with quality sunglasses will show you fish hiding in pockets and other areas. Without glasses, the stream looks like any other stream and it can be intimidating to know where to start. 

While many anglers are familiar with the term “polarized”, there is quite a bit more that anglers should consider when deciding what sunglasses are best for them. One of those things to consider is Visible Light Transmission (VLT).

Visible Light Transmission is the amount of light that’s able to pass through the lenses of your sunglasses. Generally, VLT is measured in percentage. The lower the VLT percentage, the darker the lens.

Why is Visible Light Transmission Important?

Visible light transmission is important because our eyes are often what we use to determine if a place is good enough to fish. While the surface of the water can show us some things, being able to look past the surface and into the activity that’s occurring is even better. The more we can look below the surface, the better off we’ll be when we choose our fishing style and techniques.

VLT for Fishing Sunglasses
VLT for Fishing Sunglasses

The right VLT in our sunglasses is especially important on those days when the fish are especially hard to find and finicky. We can use sight fishing to our advantage. VLT can help us locate fish, and identify the ways they’re feeding. From there, we are able to choose the size of the fly and the style that we prefer.

Quality sunglasses have a good VLT of 20% to 45%
Quality sunglasses have a good VLT of 20% to 45%

Is Higher Light Transmission Better for Fishing?

Higher Light Transmission doesn’t necessarily mean that it’s going to lead to better fishing. High Light Transmission is ideal for darker conditions. The higher the light transmission percentage, the more light that’s going to be able to get through them. If you find yourself fishing in the mornings and the evenings, then a higher light transmission is effective.

That light is present during low light can be difficult to see in with sunglasses that have a lower visible light transmission percentage. High visible light transmission glasses have a small niche, but they can prove themselves to be effective during low light conditions.

What Sunglasses Do I Recommend?

A great pair of polarized sunglasses is a game changer. Spending a little bit more for quality sunglasses is well worth it. Think of it this way – you might have hundreds of dollars wrapped up in a fly rod that just sits in the closet. You can wear sunglasses all the time. My Recommendation? Check out the Smith Guides Choice Link to Smith Optics Below 👇

Recommended Visible Light Transmission Level for Fishing

For fishing, anglers are better off fishing with sunglasses that have somewhere between 20 percent and 45 percent VLT. These percentages are ideal for a variety of light conditions.

If you find yourself fishing on especially sunny days, VLT that’s closer to 20 percent would be best. The lower VLT percentage won’t let as much light through the lens, so you don’t find yourself squinting even if you are wearing sunglasses.

If you fish in consistently cloudy or lower light conditions, sunglasses with a VLT percentage closer to 45 percent would be best. A bit more light is let through the lenses, so you won’t have to immediately remove them to be able to fully see what’s happening. The glasses will prevent some of the light from passing through the lenses while still allowing you to see clearly.

If you fish in fairly inconsistent weather with some days being sunny and some being cloudy, stick to a VLT percentage near 30 percent.

What are the Different VLT Categories

Category 4: 0-19% VLT: A VLT percentage that’s less than 20 percent is what you want if you are always in bright and sunny conditions. Anglers are well aware of those days when the water is reflecting the sunlight and it’s almost hard to see even with your glasses. Sunglasses with less than 20% VLT are also useful if you fly fish in the winter. The reflection off of the snow and water won’t be unbearable with glasses that have a low VLT.

Category 3: 20-40% VLT: Glasses with 20-40% VLT are good choices for all-purpose use sunglasses. The closer you are to 20 percent, the less light will be allowed through the lenses. The closer you are to 40 percent, the more light will be let through the glasses, so make sure you are sure of what you want.

Category 2: 40-79% VLT: Glasses with over 40 percent VLT are a good choice if you spend time in overcast or low-light conditions. The closer you get to 80 percent, the more light is going to be let through.

Category 1: 80-100% VLT: Lenses on glasses with over 80 percent VLT are essentially going to be clear. They don’t offer much in terms of protection, but they will take away some of the light from the sun, moon, and even vehicle lights.

Frequently Asked Questions

Is Polarization and VLT the Same?

Polarization and VLT are not the same. Polarization is important to fly anglers because a fully polarized lens removes some of the glare. Anglers are well aware of the challenge of fishing with a serious glare off of the water. Glare makes it nearly impossible to see through the water below the surface.

VLT percentage has to do with the amount of light that is let through the lens. Even if a lens has a low VLT percentage, it can still be non-polarized and the glare can enter. Anglers who fish in bright light with a glare will want to make sure whatever lens they choose is still polarized.

Does VLT Affect Contrast?

A lower percentage VLT will impact contrast. Since the lower percentage VLT (10-25%) is meant for light that’s especially bright and reflective, some of the light contrast is sacrificed. Things will still look realistic, but they won’t be as pure due to the color of the lenses required (usually copper or gray) to accomplish a lower percentage VLT.

Glasses with a higher percentage VLT (40-80%) generally have major color contrasts. These lenses are often a yellow, amber or deep red color. You won’t sacrifice as much contrast with a higher percentage VLT.

Does VLT Affect UV Protection?

No, VLT does not affect UV protection. These two categories are not related. Visible light and ultraviolet light are not related. Generally, most new sunglasses have significant UV protection 90% to 100%).

Last Cast

Many anglers need to put as much emphasis on their fishing equipment as they do on their sunglasses. A quick check of the VLT percentage and the polarization on a pair of sunglasses will help you know if you’re using the right sunglasses for fishing.

Remember, if you’re fishing in bright conditions with heavy sunlight, you’ll want sunglasses with a VLT closer to 20 percent. If you fish in low light and overcast conditions, stick with glasses that have around a 40 to 45 percent VLT.

Danny Mooers is a high school English teacher in Arizona with a love for fly fishing. Growing up in Minnesota gave him the opportunity to experience all types of fishing and grow his skills. After living out in the Western United States for several summers in college, his fly fishing obsession grew. Having the opportunity to share in his passion for fishing through writing is a dream come true. It’s a lifelong hobby and he strives to make it understandable for people of all skill levels

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