A Detailed Guide on The Types of Optical Lenses
Glasses are fashion accessories these days, often non-optical lenses if your eyesight is okay. But you will need optical lenses if you have any eyesight issues.
Optical lenses are transparent optical components that diverge and converge light emitted from peripheral objects. These transmitted light rays create a virtual or real picture of the objects.
There are multiple types and classifications of optical lenses, and the guide below should provide helpful insight into what they do.
What are The Different Types of Lenses?
As technology advances, so do lenses. A while back, lenses were made exclusively from glass. However, today, many manufacturers use high-quality plastic. These new versions are lighter than their predecessors, more durable than glass, and have filters that protect the eyes from ultraviolet rays.
These impact-resistant lenses are ideal for people who play sports, work in places where their eyewear can get damaged easily, or have toddlers who like playing with their spectacles.
These lenses are manufactured using a newer plastic material similar to polycarbonate. They are also impact-resistant, thin, and lightweight. They can correct vision as well.
These lenses change from clear to tinted when you expose them to sunlight. You might not need sunglasses with these types of glasses. However, they might not get dark in a vehicle with a windshield that blocks ultraviolet rays.
People 40 years and older commonly have specs with multifocal lenses, such as trifocals and bifocals. These lenses have at least two strong prescriptions to help correct eyesight issues.
- Bifocals- This is the most common kind of multifocal lens. The lens is separated into two different sections. The upper part handles distance vision, while the lower one deals with near vision. They are typically prescribed to people over 40 with trouble with proper visual focus. Most people using this lens are battling presbyopia, an age-related eye condition.
- Trifocals- These are bifocal lenses with a third separate section. It sits above the lens’ bifocal section. It is there to help one see the object within their arm’s reach, such as their phone or computer screen. The close-up section of this lens can have a straight-line, square, or crescent shape, so long as it is separated from the other parts of the lens in some way.
Progressive lenses are when no distinct lines separate the different vision correction functions. The progressive lens is the latest tech of optical lens that does not have the dividing lines you will find in trifocals and bifocals. Instead, the strength of the prescription gradually increases as one looks to expand their field of vision,
This option is usually more expensive than multifocal, with some setting you back as much as $1000. When buying a progressive or multifocal, always consider the training process you need to help your eyes adjust.
Prism lenses are designed to correct double-vision (diplopia). Diplopia occurs when the eyes refract light rays at a wrong angle, causing you to see two of the same pictures or images. Prism lenses correct this by bending that light, allowing the eyes to work together to correct the image display.
Double-vision is a rare eye condition, many times caused by the symptoms or result of another separate medical complication.
A polarized lens reduces surfaces like water, which is why it is perfect for driving and sports. However, when it comes to driving, they can sometimes make it challenging for you to see the dashboard’s liquid crystal display clearly.
Most lenses are classified as:
A Singlet or spherical lens has a curved surface that diverges or converges light. All of the cross-sections of the lens are spherical.
Unlike its spherical counterpart, a cylindrical lens has a curved face with a cylinder shape. This results in the focusing of transmitted light to a single point instead of to a line. A cylindrical lens is commonly used to help shape a laser beam or change the aspect ratio of an image.
Fresnel lenses have light, thin plastic sheets that have concentric grooves. Each groove acts as its refracting surface. These concentric grooves bend collimated light rays to a single common focal point.
A Fresnel lens is somewhat of a compromise for better optical quality and efficiency. Why? Because the material is incredibly small, very thin, and little light is lost during the transmission process.
Gradient Index (GRIN) Lenses
A GRIN lens is a simple planar lens that continuously bends light within the lens until this light finally converges into a single focal point. This is very different from a conventional lens, which mainly bends light rays abruptly when they exit from behind the lens.
A Gradient Index lens is, therefore, simple and cost-effective to employ. In addition, its ability to accurately manufacture the plane’s length leads to a lot of flexibility when fitting application parameters.
Achromatic lenses help reduce chromatic aberration, a special kind of image distortion. This image distortion happens when lenses fail to focus all color wavelengths to a single point of convergence, leading to color fringing and blurred contrast.
Achromatic lenses use two or more lens elements, at least one low-dispersion convex and one-high dispersion concave, to get their corrective function.
Optical lenses were historically manufactured from transparent glass. However, they are currently made from materials like polymers, minerals, acrylics, and arguably the most popular high-grade plastic.
With that said, they still come in all forms, shapes, and sizes. If you have been looking for optical lenses, hopefully, you have a good idea of what is available and what will best suit your lifestyle.
But if you are still unsure, you can always visit our clinic, where a well-trained eye doctor will give you a quick run-through of the lenses. We can also help you pick the suitable one for your unique situation.
Always store your lenses in a dry, clean place far from stuff that can damage them. As far as cleaning is concerned, use non-lint cloths and water. This will help you see through them clearly and help keep them spot-free.