What lenses are best for semi rimless and rimless glasses?
- Jun 5, 2025
- 3 min read
Updated: Apr 22
What Lens Thickness Should You Choose for Your Glasses?
Choosing the right lens thickness is crucial for comfort and aesthetics. If you are moderately or very short-sighted, thinner lenses are beneficial. The edge thickness of your lenses will be more visible, especially when cut to a flat finish. This allows for a groove to be cut, where your nylon can hold the lenses in place securely.
Understanding Lens Refractive Index
Lenses with a refractive index of 1.6 are ideal for prescriptions where the SPH value is between -2.50 and -4.00. These lenses are perfect for no-rim glasses and exhibit the least peripheral distortion among high-index thinned lenses. They are stronger than other lens types, making them suitable for both full and semi-rim glasses styles.
Best Lenses for Semi-Rimless and Rimless Glasses
For prescriptions between -4.00 and -6.00, a lens with a refractive index of 1.67 is recommended. If your prescription exceeds -6.00, a lens with a refractive index of 1.74 will be more suitable.
If your prescription is over -5.00, an accurate measurement of the distance between your pupils, often referred to as the PD, is essential.
Different Considerations for Long- and Short-Sightedness
Lenses for long-sightedness and short-sightedness differ significantly. Each type requires specific considerations to ensure optimal vision correction.
About Refractive Lens Index
Standard Index: The refractive index of a standard plastic spectacle lens is 1.5.
Mid Index: A mid-index lens with a refractive index of 1.6 is about 20% thinner than a standard lens.
Higher Index: A high-index lens with a refractive index of 1.67 is approximately 33% thinner, while a lens with a refractive index of 1.74 is around 42% thinner. These lenses are suitable for semi-rim glasses but may not be as strong as the 1.6 index lens.
Reflecting More Light
Lenses with a refractive index of 1.67 and higher reflect about 50% more light than standard index lenses. To reduce reflection, a multi-anti-reflection coating is often applied. This coating can lessen glare, particularly from headlights at night, although it is a matter of personal preference.
Considerations for Choosing Lenses
When selecting lenses for semi-rimless or rimless glasses, keep the following considerations in mind:
Frame Size: A frame with a lens diameter exceeding 52mm can increase lens thickness. Sometimes, this is necessary for customer choice or a wider fit.
Edge and Center Thickness: If you prefer semi-rimless or rimless frames, be aware that lens edge and center thickness can appear greater. A flat edge-finished lens is required, making them more noticeable than lenses fitted to full rim or plastic rim frames.
Plus Prescriptions: With a plus (+) prescription, the edge thickness of your lenses will need to be increased for successful glazing into the frame. This results in a thicker center and a pebbly appearance.
Minus Prescriptions: For a minus (-) prescription, the outer edges of the lenses are the thickest part. Semi-rim and rimless frame styles require thicker lenses to accommodate the small cut-in groove for the nylon wire or drilling holes in a full rimless frame. The minimum thickness on the edges of lenses is 2.5mm, which can increase depending on the prescription.
Coatings: An anti-reflection coating is an additional option for varifocal lenses. It generally comes standard on single vision lenses if they are stock (mass-produced). This coating can reduce bothersome reflections from the lens surfaces.
The Cons of Coatings: While beneficial, this coating adds extra cost. Some wearers may not prefer it because it can easily grease due to the atmosphere or handling, requiring more frequent and careful cleaning.
Making the Right Choice
Ultimately, the choice of lens thickness, thinning options, anti-glare coatings, and frame styles remains a matter of personal preference. You can contact us or visit our dispensing eyewear boutique when our store is open for more advice.
For those seeking clarity and comfort, understanding your lens options is essential. Whether you need thinner lenses or specific coatings, we are here to help you make the best choice for your eyewear needs.
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