What are aspheric contact lenses?

When it comes to contact lenses, wearing the right lens shape for the curvature of your eye is essential for achieving your clearest vision. Standard contact lenses have a spherical shape, meaning the curvature is consistent throughout the lens. But if you have an uneven cornea or irregular eye shape, aspheric contacts may be a better choice for your vision correction.

Read on to learn about aspheric contact lenses, how they work, and how they differ from other lens options.

Spheric and aspheric contact lenses

Both spheric and aspheric lenses work to improve vision by creating a smooth surface for light to pass through. While each may be prescribed for different vision needs, the main differences between them are their shape and curvature. 

Spheric contacts

Spheric contact lenses are shaped to resemble the surface of a sphere. They have a uniform curvature across their entire surface, much like a basketball or ping pong ball. 

Spheric contacts are commonly prescribed for vision correction and work well for many people. However, they can cause some distortion in peripheral (side) vision, especially for those with higher prescriptions.

Aspheric contacts

Aspheric contact lenses, sometimes called “asphere contact lenses,” have a non-spherical shape. Their curvature gradually flattens from the centre toward the outer edges, allowing the lens to bend and focus light more precisely on the retina. It also creates a larger area of usable lens, giving you a wider field of vision correction.

Aspheric contact lenses vs. aspheric optical lenses

Aspheric lenses are available in both contacts and eyeglasses. Aspheric contact lenses and aspheric optical lenses for eyeglasses are similar in design but serve different purposes.

Both types of aspheric lenses work by reducing spherical aberrations. These are optical distortions in peripheral vision that can result from the eye’s natural shape. However, these aberrations can also be caused by cataracts, corneal conditions, the after-effects of eye surgery, and other factors. 

Spherical aberrations can also affect central vision, particularly at night when the pupils are larger.

Due to their design, aspheric lenses can often provide sharper, clearer vision and a better optical image compared to traditional spherical lenses.

Aspheric optical lenses 

Aspheric glasses lenses have less curvature than traditional glasses lenses. They also curve from the centre toward the outer edges in a more gradual fashion. This allows for thinner and flatter lenses, which can be beneficial for people with higher vision prescriptions. Aspheric optical lenses help reduce the “Coke bottle” effect and bulkiness of thicker eyeglass lenses.

Aspheric contact lenses

Aspheric contacts are worn directly on the eye’s surface. This proximity to the eye reduces or eliminates distortions across the lens, helping to provide crisper, clearer vision. Aspheric contacts offer a wider field of view without the peripheral distortions often experienced with spherical lenses. 

Can anyone wear aspheric contact lenses?

While aspheric contacts may not be suitable for everyone, many people can benefit from their unique design. You may be a good candidate for wearing aspheric contact lenses if you have a severe refractive error that requires a stronger prescription. Common refractive errors corrected by aspheric lenses include:

• Short-sightedness (myopia) – Blurry distance vision
• Long-sightedness (hyperopia) – Blurry near vision
• Astigmatism – Blurry vision at all distances

They may also be ideal for people who:

• Need multifocal (varifocal) contact lenses for presbyopia (age-related eye changes that cause blurry near vision)
• Have cataracts (that can worsen spherical aberration)
• Have large pupils
• Play sports or lead an active lifestyle
• Desire a broader field of view or better peripheral vision

Your eye care provider can determine if aspheric contacts are right for your vision needs.

Can you sleep in aspheric contacts?

Sleeping in any type of contact lens increases the risk of developing serious eye infections. It’s best to remove your contacts each night and clean them as recommended by your eye doctor. You should then place them in a clean contact lens case with fresh contact lens solution.

Consult your eye care provider on the best type of solution to use for your aspheric contact lenses.

Are there different types of aspheric contact lenses?

Aspheric contacts come in the following types, each designed to meet different vision needs: 

• Soft contacts – Made of thin, flexible plastic that conforms to the eye’s surface.
• Gas-permeable contacts – Made of a rigid silicone material that allows oxygen to reach the cornea.
• Single-vision contacts – Have a single optical power throughout the lens for near or distance vision correction.
• Multifocal (varifocal) contacts – Contain two or more optical powers within the lens to improve vision at various distances. 

Benefits of aspheric lenses

There are numerous advantages to wearing aspheric contact lenses. They provide:

• A better fit for the natural shape of the cornea, often resulting in sharper vision
• Smooth transitions between viewing distances, especially for people with presbyopia
• A wider usable lens surface, enhancing peripheral vision
• Improved vision in low-light conditions

Limits of aspheric lenses

As with most contact lens options, aspheric lenses come with some limitations, such as:

 

• Cost – They tend to be more expensive than conventional lenses due to their specialised design and manufacturing process.
• Adjustment period – It may take time to get used to aspheric contacts, whether you’re new to wearing contacts or switching from another type of lens.

• Suitability – These lenses may not be the best option for certain eye conditions.

Aspheric lenses are an excellent vision correction solution for many people. To learn if you’re a candidate for wearing them, book an eye test or contact lens check at Vision Express, our trusted partner in eye care.

SOURCES:

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5. Refractive errors. Association of British Dispensing Opticians (ABDO). Accessed August 2024.
6. Aspheric lenses: Costs & comparisons (+ pros & cons). NVISION Eye Centers. October 2023.
7. Wearing contact lenses overnight. British Contact Lens Association (BCLA). Accessed August 2024.
8. How to take care of contact lenses. EyeSmart. American Academy of Ophthalmology. April 2022.
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10. GP multifocal contact lenses: The 2024 lineup. Review of Cornea & Contact Lenses. February 2024.