The Optical Knowledge Portal
Information – Education – Certification

Special visual aids for dry eye syndrome

Blue blocking and comfort filters are tried and tested visual aids to prevent burning and tired eyes. Thanks to the special properties of these filter lenses, contrast vision is also improved during computer use, while glare from screens or ambient lighting is reduced.

The difference between blue blocking filters, comfort filters and standard sunglasses is best explained by looking at the absorptive properties of these lenses:

Example for 60% tintExample for comfort filter (C500)Example for blue blocker (511)

While traditional light protection lenses reduce the transmission of visible light evenly across the spectrum, blue blocking filters cut off part of the light spectrum at a defined point and absorb all short wavelengths of light below this point. Comfort filters have only a “blue attenuating effect” since they let a small band of the blue light spectrum still pass while attenuating the major portion.

Visible blue light has a higher percentage of short wavelengths than red light, for instance, and thus carries more energy and is scattered more in the eye. This light scatter increases glare and reduces contrast vision.

These filters are also worn by people with e.g. cataract, AMD, ocular albinism or diabetic retinopathy, since they absorb a specific portion of the short-wavelength, high-energy blue light in the light spectrum. People working with a computer also benefit from this effect because computer screens also emit short wavelength light rays that can lead to disturbing light scatter and reduce the visual acuity.

ImproVision offers a wide variety of blue blocking and comfort filters in different frame styles and lens colours providing distinct filtering effects.


Courtesy of

Special visual aids for dry eye syndrome1
Special visual aids for dry eye syndrome2
Courtesy of