In this article, you will find information about why your glasses make things look curved and what you could do to avoid it. Please note if you perceive a curved image this is often tied to the lens power you need of your prescription.
When in this article I speak about avoiding a curvy image this means minimizing it as much as possible.
Your lenses have a certain power to correct your vision optimally. But when lens powers get higher some people notice side effects in the periphery of the lens. The more you move away from the optical center of the lens the more distortions you will find. This is true for every lens design in glasses.
For plus lenses, the magnification increases proportionately toward the periphery, whereas in minus lenses, the magnification decreases proportionately.
When looking at the center of a square window through a high plus lens, the corners of the window are further away from the center of the lens compared to the middle of the sides (or the middle of the top and bottom).
This means the corners will be magnified more, making the window look like a pincushion. This is known as pincushion distortion. For minus lenses, the corners receive less magnification than the middle of the sides, causing a barrel distortion.
When to Expect a Curved Image With Your Glasses?
It depends highly on the individual wearer of the glasses if he perceives a curvy image. Not only has this to do with the person and how he handles the new visual experience but also how the frame sits in on the nose and what lens design gets chosen.
The majority of people notice this effect with a prescription higher than 4 diopters
In most cases, this effect can be optimized with aspheric lenses or custom made ones. This advice applies to single vision lenses. However, with progressive lenses, most people experience things looking curvy especially in the beginning.
Why Do Things Look Curvy With Progressive Lenses?
With progressive lenses, you have the combination of the prescription for the distance vision (which produces distortions) and the transition to your reading power (which produces distortions) you need to see clearly in all distances. This requires certain changes in the lens design and brings side effects with them.
With the distortions mentioned above, you see clear but oftentimes curvy when first wearing your progressives. But with progressive lenses, you get distortions that blur the image on the sides in the lower part of the lens. Those distortions get combined in progressives and the result oftentimes is a curvy image in the middle of the lower half of the lenses.
As you can see in the picture above this experience can be very noticeably. And at first also irritating. But your brain is a fantastic system in combination with your eyes and adjusts to this experience. After a while (for some this means a few days or weeks) things do not look curved anymore. And you will see things straight again that are straight.
The picture above shows the mentioned effect you experience in the beginning in an exaggerated way. The reason therefor is simple. The more you increase the distance to the lens while observing it the more you can notice the magnification and a change in shape.
As you wear the lenses right in front of your eyes this effect gets minimized. But as I said in the first few hours or days it will be still noticeable.
A few paragraphs before I talked about an upgrade in the lens design to reduce this effect with single vision lenses. With progressive lenses, this is also possible to a certain extend. But the lenses you see in the picture above on the left side are already high-end lenses.
How to Avoid Buying Glasses That Make Things Look Curved?
There are some key takeaways to reduce the mentioned distortions with glasses.
- Wear your glasses closer to your eyes
- Use a smaller frame
- The lenses should be sitting in the perfect tilt for what they are made for (usually 8°)
- When you buy progressives go for the ones with more customization options
- When you buy single vision lenses buy free form lenses, aspheric, or atoric designs
If none of this works the alternative for you to get rid of a curvy image would be contact lenses. They will get rid of this problem right away.
I wish you a great day.
