Lens Prescription Changes: Why Do Objects Appear Enlarged?

Q: Lens Prescription Changes: Why Do Objects Appear Enlarged?

Hello, Ah-Hsiang： Myopia is corrected with concave lenses, which means that the deeper the lens, the smaller the image of the object appears. <br>As for the magnification sensation you mentioned, it was explained in the previous article. <br>In fact, you don't need to understand

Follow-up question #182843 regarding eyeglass lenses?

Dear Dr.
Gao,
Thank you very much for your responses and guidance in articles #182843 and #182888; I have greatly benefited from them.
Regarding the increase of 25 degrees in my right eye prescription last year (2021), I found that wearing the new lenses indeed makes my vision clearer and brighter.
However, I also experience a sense of magnification when looking at objects.
You mentioned, "Usually, a decrease in myopia leads to a sense of magnification..." (the rest is omitted).
I am a bit confused about this.
Are you suggesting that intentionally reducing the prescription will cause a sense of magnification when wearing the glasses? Or are you indicating that my myopia is lower, but the prescription is set too high, which results in the sense of magnification? I would appreciate your clarification on this matter.
Thank you again, Dr.
Gao.

Axiang, 40~49 year old female. Ask Date: 2022/06/13

Dr. Gao Pilin reply Ophthalmology

Hello, Ah-Hsiang: Myopia is corrected with concave lenses, which means that the deeper the lens, the smaller the image of the object appears.
As for the magnification sensation you mentioned, it was explained in the previous article.
In fact, you don't need to understand it; it's an optical phenomenon that doesn't require much attention.
Just get used to it, as long as the prescription is correct.

Reply Date: 2022/06/13

More Info

Understanding changes in lens prescriptions and their effects on vision can be quite complex, especially when it comes to how objects appear when viewed through corrective lenses. The phenomenon of objects appearing enlarged or distorted can be attributed to several factors related to the optics of the lenses and the individual's visual system.

When you mention that after increasing the prescription by +25 degrees in your right lens, objects appear larger, it is essential to clarify the mechanics behind this. Generally, when a person has myopia (nearsightedness), they require concave lenses (negative diopters) to correct their vision. If the prescription is reduced, the lenses become less concave, which can lead to a magnifying effect, making objects appear larger than they are. This is because the eye's natural lens and the corrective lens work together to focus light on the retina, and changes in the curvature of the lens can alter the way light is refracted.

In your case, if your right eye's prescription was increased, it could mean that the lens is now more convex than before. Convex lenses (positive diopters) can create a magnifying effect, which is why you might perceive objects as larger. This effect is particularly noticeable when looking at objects at a distance or when the lens is designed to correct for hyperopia (farsightedness) rather than myopia.

Moreover, the perception of size can also be influenced by the contrast and color of the objects being viewed. For instance, if you are looking at a brightly colored object against a contrasting background, the brain may interpret the size differently due to the way it processes visual information. This is known as the "size-contrast illusion," where the perceived size of an object can change based on its surroundings.

It's also worth noting that adaptation plays a significant role in how we perceive changes in our vision. When you first wear new glasses, your brain may take some time to adjust to the new visual input. This adjustment period can lead to temporary sensations of distortion or size changes until your visual system recalibrates to the new prescription.

In summary, the feeling of objects appearing larger after a change in your lens prescription can be attributed to the optical properties of the lenses, the nature of your refractive error, and how your brain processes visual information. If you find that this sensation persists or is accompanied by discomfort, it would be advisable to consult with your eye care professional. They can conduct a thorough examination to ensure that your prescription is accurate and that there are no underlying issues affecting your vision. Regular follow-ups are essential, especially if you have a history of significant changes in your prescription, as they can help monitor your eye health and ensure optimal visual clarity.

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