The materials, lightest first
Frame materials are not all alike, and the weight difference between the lightest and the heaviest common material is large enough to feel.
- Ultem and the other engineering plastics. Ultem is a plastic developed for aircraft interiors: stiff, heat resistant, and so light that a full rim frame in it weighs less than most rimless metal frames. It takes thin rims without flexing, which is why it suits geometric and angular shapes. The Ultem glasses guide covers it in depth.
- The ultra-light polymers (PPSU and its relatives). The same family as Ultem, used for crown panto and panto shapes with spring hinges. Light, flexible under a knock, and the material that bends back rather than snapping.
- TR90. A nylon based material that is light and flexible, the standard for sports sunglasses and increasingly for everyday frames. Slightly heavier than Ultem, far more forgiving of a sit-on.
- Titanium and beta titanium. The lightest metal used in eyewear, and the strongest for its weight. A titanium temple is thinner than a steel one carrying the same load, so the frame is lighter and the arms disappear. Beta titanium is the springy alloy used for temples that need to flex. The titanium glasses guide and the titanium glasses collection cover the range.
- Thin acetate. Acetate is the heaviest common material by volume, so an acetate frame is only light when the rim is thin and the shape small. A well cut thin acetate frame can sit close to a titanium one; a chunky acetate frame never will.
- Stainless steel and other metals. Thin, but dense. Fine in a rimless or a half rim, heavy in a full rim.
Why the rim matters as much as the material
Two frames in the same material can differ in weight by half. The rim is where the material goes: a full rim around a large lens uses the most, a thin full rim around a small lens the least, and a rimless or half rim frame almost none. So a small thin-rimmed acetate frame can weigh less than a large full-rim Ultem one. When you compare two frames, compare the rim and the lens size together with the material, not the material alone.
The lenses weigh more than you think
On an optical frame the lenses are usually the heavier half, and the frame material makes no difference to them. Two things decide lens weight: the size of the lens, which the frame sets, and the lens material, which you choose when you add your own lenses. Smaller lenses weigh less, which is the second reason a smaller frame feels lighter.
Signs a frame is too heavy for you
- Two red marks on the sides of the nose after an hour, or a dent where the pads sit.
- The frame slides down during the day even though it fits at the bridge; weight pulls a frame down the nose, and the glasses keep sliding down guide covers the other causes.
- Soreness behind the ears by evening, which is weight the ears are carrying because the nose cannot.
- A headache across the bridge of the nose that goes when the glasses come off.
If two or more of these are familiar, the next frame should be a step down in weight, and the step is usually from acetate or steel to Ultem, titanium or TR90.
Making a light frame stay put
Light helps, but a light frame still has to sit. Three details do the work. Nose pads on arms spread the weight and can be set for your nose; the nose pads for glasses guide explains how, and the adjustable nose pad glasses collection lists the frames with them. Spring hinges let the temples open a little wider than the head and hold with a light grip rather than a pinch. And a bridge cut for your nose keeps the frame level; many of our frames are cut for a lower nose bridge, listed in the low bridge fit eyeglasses collection, so the frame rests on the nose instead of the cheeks.
Light and thin are not the same
A thin frame is one with a narrow rim; a light frame is one that weighs little. They overlap but they are not the same thing, because a thin steel frame can outweigh a thicker Ultem one. The thin frame glasses guide covers the look; this guide covers the weight. If you want both, the answer is a thin rim in titanium or Ultem.
MUJOSH lightweight glasses
Five frames from the eyeglasses collection, ranked by material and rim, lightest first. No weights are printed because none are published on the product pages; the order follows the materials above.
- Alio XZ, $99: a crown panto in ultra-light material with spring hinges and a low bridge fit, three colourways. The lightest frame in the range by material, with the two fit details that keep a light frame on: spring hinges and the lower bridge cut.
- Ultem, $99: a geometric multi-cut frame in Ultem with a mortise and tenon hinge, five colourways. Thin rim, stiff material, the frame you forget you are wearing.
- Beta Pitot, $135: a square-round frame with beta-titanium temples and a low bridge fit, two colourways. The temples are the light part; the front keeps a little presence.
- Halo, $119: a rounded retro frame in lightweight acetate with adjustable nose pads, two colourways. The acetate frame cut thin enough to compete, with pads on arms to spread what weight there is.
- Trendy Diamond, $99: a diamond-cut cat eye in acetate with a low bridge fit, two colourways. Small lenses keep the weight down on the one frame here with a shape to show off.
For sunglasses the same materials apply and the lightweight sunglasses guide ranks the sun range.
The bottom line
Lightweight glasses are a material question first: Ultem and the ultra-light polymers, then TR90 and titanium, then thin acetate, with steel full rims at the heavy end. The rim size and the lens size change the answer as much as the material, and on an optical frame the lenses are the heavier half. Red marks, sliding, sore ears and a bridge headache are the signs to step down in weight. Spring hinges, pads on arms and a bridge cut for your nose make a light frame stay put. In the MUJOSH range, Alio XZ and Ultem are the lightest by material, Beta Pitot carries titanium temples, and Halo and Trendy Diamond are the acetate frames cut light.
Weight matters more the longer glasses are worn each day; the glasses for women over 50 guide makes it one of its four rules.
Weight is one of the six reasons a frame hurts behind the ears; the glasses hurt behind ears guide covers the other five.
Frequently asked questions
What is the lightest material for glasses frames?
Ultem and the ultra-light polymers in its family, then titanium among the metals and TR90 among the flexible plastics. Acetate is the heaviest common material and is only light when the rim is thin and the lens small.
Are titanium glasses lighter than plastic?
Lighter than acetate, yes; lighter than Ultem or TR90, usually not. Titanium is the lightest metal used in eyewear and the strongest for its weight, which is why it suits thin temples and rimless frames.
How do I know if my glasses are too heavy?
Red marks or dents at the nose, sliding during the day despite a good fit, sore ears by evening, or a headache across the bridge that stops when the glasses come off. Two of those together point to a lighter frame.
Which MUJOSH glasses are the lightest?
By material and rim: Alio XZ (ultra-light material with spring hinges) and Ultem (lightweight Ultem) first, then Beta Pitot with its beta-titanium temples, then Halo and Trendy Diamond in acetate cut thin. No weights are printed because none are published for the frames.
