Aberrations

Why do my glasses change the size of my eyes?

31. January 2023, Author: Paula Blahová, Photo: Jakub Čaprnka

Physics is to blame for everything! Plus diopters – that is, diopters for close distance – magnify the image. Simply put, they work like a magnifying glass, and our eyes naturally appear a bit larger than they actually are. With minus diopters, the opposite effect occurs, making the eyes seem smaller. In optical terms, we call this phenomenon aberration. The intensity of aberration depends on the strength of the diopters, and at lower values it's almost unnoticeable.

Thinning the lens reduces aberration

With higher diopters, we'll never completely avoid the change in eye size, unfortunately. But we can help it along! Clever physics minds figured out long ago that the deformation effect can be suppressed with a higher refractive index. The thinner the lens, the less noticeable the change. By investing in thinning, we soften the distortion.

We can only eliminate it completely by wearing contact lenses. At ZITA, though, we regularly emphasize that lenses are a supplement, not a replacement for glasses. The best possible solution is therefore a thorough eye examination and choosing suitable glasses. We're happy to help you with both at the shop! After all, a slight difference in eye size doesn't outweigh the fact that glasses significantly improve our lives.

By the way, aberration isn't the only image distortion that eyeglass lenses can cause. Every now and then, a small rainbow appears when we look through our glasses. This is caused by the lens material, which breaks down white light into a spectrum of colors under certain lighting conditions. This effect is most visible when looking toward the periphery of the lens. That's why precise centering is so important for a clear image. Come clarify your vision with us!