Contact lenses can have countless benefits when worn and cared for as directed. You can enjoy more natural vision, with no frame edges sneaking into the corner of your eye. Contact lenses are also available in various styles and types.
Multifocal contact lenses provide vision care options for adults and children. However, how the lenses work depends on what the lenses are designed for—enhancing vision for multiple distances or myopia control.
How Do Contact Lenses Work?
Before moving on to multifocal contact lenses, let’s review how standard contact lenses work. At your routine eye exam, your optometrist evaluates how your eye focuses light, determining your refractive error (a vision problem caused by irregular eye shape).
Refractive errors prevent light from focusing correctly on the retina, the light-detecting tissue at the back of the eye. Prescription lenses can increase or decrease the focal power of the cornea (clear front of the eye).
For example, contact lenses for nearsightedness (myopia) increase focal power, so light reaches further into the eye to focus directly on the retina. Conversely, lenses for farsightedness (hyperopia) decrease focal power to pull light back to focus directly on the retina.
It’s like aiming for a basketball hoop. People with myopic eyes don’t shoot far enough, so the ball barely touches the rim. People with hyperopic eyes shoot too far, and the ball (or light) hits the backboard too hard, missing the net (the retina). Prescription lenses help correct your aim, so light (or the ball) gets nothing but net.
Multifocal vs. Multifocal
Like standard lenses, multifocal contact lenses help redirect light (or improve your cornea’s aim), so light focuses on the retina. However, multifocal contact lenses contain multiple focal powers. So instead of correcting one type of refractive error, the lenses can refocus light in numerous ways.
There are 2 types of lenses referred to as multifocal:
- Multifocal lenses for multiple distances
- Multifocal lenses for myopia control in children
Correcting Multiple Distances
Most people don’t have perfectly round or smooth eyes. Slight irregularities may barely alter our vision or eye health, so our eyes can easily compensate for the little flaws. But when you have a refractive error, it’s because there’s a significant enough irregularity that it impacts how your eye works.
Many people with refractive errors either experience farsightedness (hyperopia) or myopia (nearsightedness) because the problems are opposite. Myopia is caused by a too-long eye or steeply curved cornea. Hyperopia is caused by a too-short eye or too slightly curved cornea.
However, astigmatism (a cornea or lens with mismatched curves) can affect near and far vision. Additionally, when people age, natural changes to the eye’s lens can cause blurry near-vision (presbyopia), which can occur alongside myopia—meaning they have poor near and far vision.
Standard contact lenses only contain one focal power, correcting only one refractive error. But multifocal contact lenses can have multiple focal powers to correct multiple distances, including near, far, and in between.
For example, a bifocal contact lens has 2 focal powers. There are 2 designs possibilities:
- An upper half for near vision & a lower half for far vision
- A center section for distant vision & an outer ring for close vision
The sections or rings mimic how we naturally view distances, like looking downward to read but upward to look further away.
Myopia or nearsightedness causes blurry distance vision. But it can also increase the risk of developing sight-threatening conditions as the eye grows too long. Myopia control methods aim to slow eye growth in children, preventing myopia from progressing.
Multifocal contact lenses for myopia can reduce eye growth by refocusing light inside the eye. In standard lenses for nearsightedness, the prescription increases focal power, so light focuses directly on the retina. But because the myopic eye has an irregular, elongated shape, light also focuses behind the retina.
The additional light reaching behind the retina is known as peripheral defocus. In other words, the eye receives a signal that light is focusing incorrectly behind the retina—that eye is too short. So, the eye continues to grow, trying to bring the peripheral light rays into focus.
Multifocal contact lenses for myopia sharpen distance vision and slow eye growth. The lens features a bullseye design. The middle section increases focal power to focus central light directly on the retina. An outer ring redirects peripheral light, pulling it to focus on the retina. Without peripheral light focusing behind the retina, the eye stops receiving signals to keep growing.
While the results vary between brands, overall multifocal myopia control lenses can significantly help slow eye growth.
Are Multifocals a Good Fit for You?
Multifocals were initially designed to help people with multiple refractive errors enjoy convenient vision correction (without switching between multiple prescription lenses). But myopic control lenses can also help prevent risks to eye health. So whichever type of multifocal contact lens you look at, there are benefits.
But are multifocals a good fit for you? See us to find out! At Arena Eyeworks, we’re committed to providing total vision care. We prioritize your eye health and comfort, striving to ensure your vision remains clear and comfortable. Book an appointment to learn about your lens options.