Do you need to wear aspherical lenses?

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Choosing new glasses involves many factors, including the type of lens you are going to buy. If you have a strong prescription, you might consider aspheric lenses.

What are aspherical lenses?

There are many types of eyeglass lenses, including aspherical lenses. While regular or standard lenses have a circular shape, aspherical lenses have a variable curve across the lens. They are thinner, flatter and improved lenses.

Understanding light and vision

Most vision problems arise due to the way light is focused using your retina. The retina is the innermost part of your eye that detects light and helps transform it into three-dimensional images. It works with the cornea, which is the outermost layer of your eye, and the lens, which is an inner part of your eye.

The cornea and lens bend (i.e. refract) light as it enters your eye and focus it on your retina. The cornea is fixed, but the lens changes shape when you focus on something near or far. The shape of your eye or cornea, however, can alter the way light bends and cause it to miss your retina or not focus directly on it. These are called refractive errors and can cause blurred vision.

Refractive errors can cause nearsightedness where you can see well up close but have trouble seeing farther away. They also cause farsightedness, where you can see far objects well but not near ones. You can correct these problems with glasses. The goal is to place a lens in front of your eye that helps focus light directly onto your retina. The result is clearer and more comfortable vision.

Curved Lenses vs Aspherical Lenses

Most lenses have a constant curve that helps bring the light into focus. A concave lens curves inward and helps with nearsightedness, while a convex lens curves outward and helps with farsightedness.

There are downsides, however, if you have a strong prescription with significant curvature. With a stronger prescription, your lenses are thicker and heavier and may make your eyes appear larger. In these cases, aspherical lenses are a good option.

Aspherical lenses change the degree of curvature from the center of the lens outward. The curve is flatter, so the lens is thinner and lighter.

How do aspherical lenses work?

Because the curve varies and flattens out toward the edge of the lens, aspherical lenses have a larger usable area than regular lenses. This larger surface area means that aspherical lenses can bend light more effectively than regular lenses.

In ordinary lenses, the light that hits the edge of the lens is focused in a different place than the light in the center. The result is blurry vision in your periphery.

If you have a strong prescription, you will need a thick lens to deflect the light well. If you are farsighted, you will need more thickness in the center of your lenses. Your eyes will look magnified and create what is sometimes called glasses eyes or the look of a soda bottle. You might feel self-conscious about your glasses and their appearance, but aspheric lenses can help.

With a flatter curve, there is less center thickness and less eye magnification. They also correct distortion and create a higher quality image.

Aspherical lenses can also improve your peripheral vision. The lens is thinner and lighter, so it adapts better to the frame of your glasses.

What are aspherical lenses used for?

You may want to choose aspherical lenses when you have a strong prescription or experience dramatic refractive errors. Dramatic refractive errors mean you have significant problems with the way light focuses on your retina, which means you’ll need stronger corrective action.

Relevant issues include conditions such as:

  • Myopia, where objects in the distance are blurry
  • Hyperopia, where objects close to you are blurry
  • Astigmatism, where near and far objects are blurry or distorted
  • Presbyopia, where you can’t see things up close as you age

Your eye doctor might recommend both aspherical and high-index lenses. Where aspheric refers to the lens profile, high index refers to the lens material and thickness. The higher the index, the thinner the lens.

It’s called a high index lens because it has a high index of refraction, which means that light travels quickly through the material. The material bends light more efficiently, making it more effective at correcting high refractive errors.

An aspheric and high index option means your lenses will be easier to wear with a strong prescription.

Advantages of aspherical lenses for glasses

Aspherical lenses will make your glasses lighter, thinner and more comfortable to wear. Thicker lenses are harder to fit into your eyeglass frame and more likely to pop out. If this happens often, you risk damaging your lenses and frames, which can lead to greater expense.

Aspherical lenses can fit most frames, so you can wear almost any style, including rimless or plastic frames. These also prevent distorting the appearance of your eyes and can help you feel confident when wearing glasses.

Disadvantages of aspherical lenses

Aspheric lenses can be more expensive to manufacture, which means your glasses will cost more. You might be willing to pay more if it helps your eyes look less magnified, but replacing your current glasses could be expensive. You’ll probably also want anti-scratch and anti-reflective coatings, which will add to the cost.

While high index aspherical lenses have a better profile for heavy prescriptions, high index lenses are not impact resistant. They are more fragile, so you will have to be very careful with them.

Conclusion

Aspheric lenses are a great option for heavy prescriptions. They give you more comfort, more access to frame styles, and reduce magnification of your eyes. These contacts can give you confidence and help you feel good about your personal style.

Ask your eye doctor if aspheric lenses are right for you.

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