Blue light is a high-energy visible light emitted by the sun, digital screens, and LED lighting. Many people seek to filter this light to mitigate symptoms of digital eye strain, such as dry eyes, headaches, and visual fatigue. It is common to wonder if an existing pair of glasses can be effectively modified to include this filtering capability. The answer involves options ranging from laboratory-applied modifications to simple external accessories.
Retrofitting Existing Lenses
Applying a blue light filter directly to an existing lens surface is a viable option, though the process is not always simple. Professional optical labs can apply a blue light filtering coating, similar to an anti-reflective coating, to your current prescription lenses. This service typically requires sending your glasses away for several days and depends entirely on the lens material and condition.
Lens Condition Requirements
The success of a professionally applied aftermarket coating hinges on the lens surface being pristine. Existing scratches, chips, or embedded oils can be magnified or permanently sealed by the new layer. If your glasses already have an anti-reflective coating, the new blue light layer may not adhere properly, or the existing coating may need to be stripped first, which risks damaging the lens itself. If lenses are heavily scratched, an optician may recommend replacing them entirely with new ones that have the filter integrated. Consumer-grade DIY spray-on filters and wipes exist, but they lack the durability and tested consistency of a professionally applied vacuum-deposited coating.
External Attachments for Filtering
For a non-permanent and immediate solution, external attachments offer a straightforward way to add blue light protection. The most common form is the clip-on filter, which features a small mechanism that attaches directly to the top of your existing eyeglass frame. These are convenient because they can be quickly flipped up or removed when blue light filtering is not desired, such as when viewing color-sensitive work.
Fit-Overs and Drawbacks
Another option is “fit-over” glasses, which are essentially a larger pair of blue light filtering glasses designed to be worn over your primary spectacles. Both clip-ons and fit-overs are generally more affordable than professional lens modifications, but they introduce a second layer of lens material. This double-layer can sometimes increase glare and reflections, and the added weight or bulk may negatively affect the comfort and aesthetics of your regular glasses. These attachments can also feel clunky or slip out of position with movement.
Evaluating Performance and Durability
The effectiveness of blue light filtering is measured by how much light is blocked in the problematic range, typically between 380 and 450 nanometers. Integrated or professionally applied coatings offer a seamless look and usually filter a portion of the blue-violet light spectrum, often around 20% to 40%. However, these coatings can degrade over time due to wear, improper cleaning, or exposure to environmental factors.
Filtration Levels and Trade-offs
External attachments, especially those with an amber or yellow tint, can often block a much higher percentage of blue light, sometimes filtering up to 60% or more. This higher filtration comes at the cost of color distortion, as a yellow tint is necessary to visibly remove the blue spectrum. While coatings are expected to last the life of the lens if cared for properly, their effectiveness may decrease after two to three years of frequent use. Clip-ons and fit-overs have a longer inherent lifespan but are more prone to physical damage like scratches or breakage of the clip mechanism. Ultimately, if you spend long hours in front of screens and require maximum visual quality and comfort, purchasing a new pair of lenses with the blue light filter technology integrated directly into the lens material is often the most comprehensive solution.