How to Choose the Right Lens Thickness for Your Eyeglasses

The selection of the correct eyeglasses directly impacts your appearance and changes the overall look of your face. To be specific, lens thickness can make a big difference. Whether you are seeking prescription-based eyeglasses or any other type of lens, the lens thickness for eyeglasses should be chosen based on different factors. 

In this regard, you should strongly focus on factors such as the comfort level, edge visibility, weight and compatibility with your desired frame. 

This guide will walk you through the comprehensive details that you must follow to choose the right lens thickness. Especially if you are looking for high-index lenses, plastic lenses, or any other lens type, this guide is just for you. 

Why Lens Thickness Matters

Well, lens thickness is important because it involves technical specifications. Besides, if you are planning to wear your eyeglasses for a longer duration, you should not choose a lens that weighs too much, as it may not be comfortable to wear. Moreover, they also impact the aesthetics of your glasses. 

• If you have strong minus prescriptions, they will create visible thick edges. On the other hand, strong plus prescriptions may lead to noticeable centres, which may not have an overall good appeal. 

• For example, if you choose a very thick lens, it may create the so-called “coke bottle” effect, drawing unwanted attention.

Coke Bottle effect: Based on the prescription, the lens will appear to be very thin or thick at the centre, creating a visible ring. 

However, it is worth noting that the thickness of the lens not only depends on the prescription, but also on the frame size, lens material, thickness of the spectacles rim, and the individual eye’s pupillary distance or monocular pupillary distance. 

Factors That Impact The Lens Thickness 

As stated above, multiple factors play a significant role in defining how thick your lenses will be. It is better to have clarity on these factors beforehand so that you can make the correct choice for lens thickness.

• Prescription strength: If you choose a standard material for stronger prescriptions, the lenses will eventually be thicker. For example, both a −2.00 D lens and a −7.00 D lens look and feel very different from each other. 

• Pupillary distance (PD): If your PD for the eye is smaller, then the edge thickness will be greater for a minus-powered lens. Matching the monocular PD of each eye is mandatory. However, sometimes, negligent dispensers, to make the edge of minus lenses appear thinner, fit lenses at larger PDs. This is inappropriate dispensing and leads to adverse effects in the long term on convergence of the eyes.  

• Frame size: The choice of frame size also matters a lot. For example, if you are choosing a smaller frame, the edge thickness is likely to be less, as compared to large or oversized frames, especially in case of short-sightedness corrections. 

• Frame rim type: Full-rim frames can easily conceal the edge of the lens well. Such frames pair very well with slightly thicker lenses. On the contrary, rimless or semi-rimless frame styles may expose the lens edge completely. Hence, they are paired well with thinner lenses. 

• Frame shape: Thicker lenses go very well with round or oval smaller frames. Meanwhile, if you are choosing high-index lenses, pair them with oversized or rectangular frames to create a balanced look. 

• Lifestyle/purpose: For all-day wearability and for kids' glasses, you may prefer specific lens materials such as polycarbonate. However, they may be slightly on the thicker side. 

• Budget: Before coming to a decision, it is important to consider the pricing factor as well. Thinner high-index options are generally costlier than the standard plastic lenses. However, the costlier the lens, the higher the aesthetics and comfort will be. 

Understanding Lens Index 

The refractive index of a lens defines how much the material of the lens can bend light. In short, if an efficient material is used, less of it will be used to redirect light for the same prescription. 

This is the reason why higher index lenses are thinner for the same prescription as compared to lower index lenses. To understand this better, let’s take a glance at this lens index table: 

Which Is The Best Lens Material For You 

Not every lens material suits every individual; hence, it is important to compare the available options based on factors such as weight, thickness, and practical performance: 

CR-39 / Standard Plastic

This is one of the most optically pure lens materials, having an Abbe value of around 58, the highest of any standard optical plastic. This high Abbe value means low chromatic aberration (color distortion) and excellent visual clarity. Additionally, these lenses pair well with mild prescriptions ranging from roughly ±0 to 3.00 D and suit most frames well. 

Polycarbonate

Lenses made out of this material are lighter than CR-39. The most noteworthy advantage of this lens material is that it is impact-resistant. In short, they work really well as safety glasses, sports eyewear, and kids' glasses. Talking about the thickness of the lens, it is generally 10 to 15% thinner than standard plastic. 

Trivex

This lens material is known for its excellent optical quality and strong impact resistance, especially if we compare it to polycarbonate lenses. Along with being lighter, this lens type offers clear peripheral vision. However, these lenses may be on the pricier side. 

Glass Lenses

High-index lenses for glasses generally perform well when it comes to scratch resistance as well as optical clarity. However, they may be heavier when compared to their plastic alternative. Besides, they are prone to shattering on impact. 

High-Index Plastic

If you have a strong prescription, high-index plastic lenses will be the perfect choice for you. This is because they come with a manageable weight and are about 30% thinner than standard plastic lenses. In short, they are highly suitable for high plus and high minus prescriptions. 

Which Frames Work Best With Thicker Lenses?

Alongside lens thickness, frame style also plays a vital role in ensuring how the lens thickness appears to others and how comfortable your glasses will feel during all-day wear. 

• Full-rim frames: These are the most acceptable choice for thicker lenses because they can conceal the lens thickness very well. Highly recommended for those having a moderate to strong prescription. 

• Rimless and semi-rimless frames: Both these frame types expose the edge of the lens entirely. Individuals with prescriptions that go beyond ±3.00 D should not choose such frames. However, you can still choose these frames if you choose a thinner lens material. 

• Smaller frames: Lens width also plays an important role because it helps cut the edge thickness by 20 to 40%, especially for minus prescriptions. 

• Large or oversized frames: These are not ideal for minus prescriptions because they increase edge thickness substantially. If you still choose this frame style, it is essential to pair it with high-index lenses. 

Lens Thickness by Prescription Range - R. Kumar Opticians Recommended 

Matching the correct lens type with the required prescription range can make a huge difference in balancing the proportions. Here’s what it means for you: 

• Mild to Moderate Prescriptions (±0 to 3.00 D) + Standard plastic or Polycarbonate = Less lens thickness & superior optical clarity. 

• Moderate to Strong Prescriptions (±3.00 to 6.00 D) + High-index materials = Perfectly balances appearance and weight. 

• Strong Prescriptions (Beyond ±6.00 D) + 1.67 or 1.74 high-index lenses = Lesser lens thickness and lightweight. 

Quick Tips to Reduce Visible Lens Thickness

Even without trying much, you can still achieve that balanced yet classy look. In case you do not want to invest in a high-index lens at this point, you may try doing the following: 

• Choose a smaller frame 

• Prefer full rim and acetate frame over rimless or semi-rimless frames

• If you have a prescription above ±4.00 D, choosing a high-index lens is highly recommended 

• With thick lenses, select dark or patterned frames that take the attention away from the lens 

For personalised advice on pairing the right lens with the perfect frame, get in touch with the certified optometrists at R. Kumar Opticians. We will be glad to help you find the ideal match based on your prescription and style.

Frequently Asked Questions

Will thicker lenses affect the clarity of my vision?

No, the lens thickness of your eyeglasses doesn't have anything to do with the vision clarity. The clarity of your vision depends entirely on the chosen lens material, the prescription accuracy, and any applied coating. 

Are high-index lenses worth the extra cost?

If you have a prescription that goes beyond ±4.00 D, high-index lenses are generally worth the cost. This is because they are comparatively thinner than other lenses, are lightweight, and improve the overall appearance. 

Do high-index lenses cost more?

High-index lenses are generally slightly pricier than standard plastic lenses. This is because the material itself is highly expensive. 

Which frame size is best for thick lenses?

If you are unable to find a lens that is affordable as well as thin, you should focus on the next thing, i.e., finding the perfect frame type and size. Try pairing thicker lenses with smaller, full-rim frames.