Lens width
The width of one lens in millimetres, typically 40 to 58. This is the number that most affects whether a frame looks proportioned on your face. Two frames with the same lens width will look similar in scale even if the shapes differ.
Guide
Finding a Frame That Fits
Two things decide whether a frame works: whether it physically fits your face, and whether its lines suit your face. The first is measurable and non-negotiable. The second is judgement, and it is where a good optician earns their keep. This guide covers both, including how to read the numbers printed inside your current temple arm.
- The quick test
- The frame should sit level, not touch your cheeks when you smile, and not slide when you look down
- The numbers
- Printed inside the temple, usually as 52□18‑140
- Fitting
- Free and unlimited on any frame, bought here or elsewhere
Face shapes
The contrast principle, and its limits
The general idea is that frames look best when their lines counter your face's lines rather than repeat them. It is a useful starting point and a poor verdict.
| Face shape | Characteristics | Frames that usually work | Usually less flattering |
|---|---|---|---|
| Round | Soft curves, width and length similar, full cheeks | Rectangular, square and angular frames. Anything that adds definition and horizontal line | Small round frames, which echo the face's curves |
| Square | Strong jaw, broad forehead, angular line | Round and oval frames, softer edges, thinner rims that ease the angles | Heavy square frames that double the existing lines |
| Oval | Balanced proportions, gently curved jaw | Almost anything. Match the frame width to your face width and you have latitude | Oversized frames that swamp the balance |
| Heart | Wider forehead, narrower chin | Bottom-heavy or rimless designs, light colours, oval and round shapes | Heavy top rims and decorated brow lines |
| Long or oblong | Face notably longer than wide | Deeper frames with strong horizontal lines, decorative or contrasting temples | Narrow, shallow frames that stretch the face further |
| Diamond | Narrow forehead and jaw, wide cheekbones | Cat-eye, oval and rimless frames with detail on the brow line | Narrow frames that emphasise the cheekbones |
Colouring matters more than people think
Warm complexions, meaning skin with golden or olive undertones, generally sit well with gold, bronze, tortoiseshell, warm browns and olive. Cool complexions, with pink or blue undertones, suit silver, gunmetal, black, blue and rose tones.
This is the part most people skip, and it does more for how a frame reads on your face than the shape does. Hold a gold frame and a silver frame up next to your jaw in daylight and the difference is usually immediate.
And then ignore all of it
Plenty of people look excellent in the frame the chart says they should avoid. Face shape guidance is a way of narrowing down a wall of options to a shortlist, not a set of rules that overrides what you can see in the mirror.
What we will not do is tell you a frame works when it does not. That is the one place where our opinion is worth more to you than agreement.
The numbers
How to read the inside of your temple arm
Every frame carries its measurements, usually printed inside the left temple as something like 52□18‑140. Once you can read them, comparing frames becomes simple.
Bridge width
The gap between the lenses, typically 14 to 24 millimetres. Too narrow and the frame pinches and sits high; too wide and it slides down your nose. This is the measurement most often wrong on frames bought online.
Temple length
The length of the arm, typically 135 to 150 millimetres. It needs to reach your ear comfortably and then curve down behind it without pressing. Too short and it grips; too long and the frame slips forward.
Total frame width
Roughly double the lens width, plus the bridge, plus the rim thickness on both sides. The front of the frame should be about as wide as your face at the temples. If it is wider, the frame will slide; if it is narrower, it will press.
Pupillary distance
Not printed on the frame. This is the distance between the centres of your pupils, and it determines where the optical centre of each lens has to sit. It is measured on you, not on the frame, and getting it wrong causes eye strain and headaches that people often blame on the prescription.
Bridge fit, and why it varies
Nose bridges differ in height and width more than most people realise, which is why the same bridge measurement can fit one person well and another badly. Frames with adjustable nose pads accommodate a wider range; moulded acetate bridges do not, so they have to be the right shape from the start.
If your current glasses leave red marks either side of your nose, sit too low, or need constant pushing up, the bridge is the thing to change. Bring them in and we will show you what is happening.
Materials
What frames are made of, and what that means for you
Material decides weight, adjustability, durability and how the frame ages on your face.
| Material | Feels like | Strengths | Trade-offs |
|---|---|---|---|
| Acetate | Substantial, warm to the touch | Rich colours and patterns, holds bold shapes, hypoallergenic, can be reshaped with heat | Heavier than metal, and can loosen over years of heat and wear |
| Titanium | Almost weightless, slightly springy | Extremely light and strong, corrosion resistant, hypoallergenic. Excellent for daily wear | Costs more, and fewer bold colour options |
| Stainless steel | Thin, firm, cool | Strong for its thickness, good value, holds fine shapes well | Less flexible than titanium, and some grades can irritate sensitive skin |
| TR90 and nylon | Light, slightly flexible | Bends and springs back rather than snapping. The sensible choice for children and sport | Limited to certain shapes, and cannot be adjusted as precisely |
| Memory metal | Very light, noticeably springy | Returns to shape after being twisted or sat on. Forgiving of rough handling | Springiness makes fine fitting adjustments harder to hold |
| Rimless mounts | Barely there | Minimal, light, and the lens shape can be customised | Lenses must be drilled, so they need to be tougher material. Not ideal for very strong prescriptions |
If you have reacted to frames before, titanium and acetate are the two to look at. Reactions are almost always to nickel in metal alloys, and both of those avoid it.
Getting the fit right
Five checks you can do in the mirror
Do these with the frame on your face before you commit. They take under a minute and catch most problems.
Does it sit level?
Look straight ahead in a mirror. The top rim should run roughly parallel with your eyebrows, and both sides should sit at the same height. A frame that sits crooked is a frame that needs adjusting, which is a five minute job, not a reason to reject it.
Where are your eyes in the lens?
Your pupils should sit slightly above the vertical centre of the lens and roughly central horizontally. Eyes sitting low or off to one side means the frame is the wrong size or shape for your face, not something a fitting can fix.
Smile.
If the bottom rim rides up and touches your cheeks, the frame is too deep or sitting too low. This is the single most common cause of a frame that feels annoying without the wearer knowing why.
Look down.
Tilt your head forward as if reading your phone. The frame should stay put. If it slides, the bridge is too wide or the temples need adjusting behind your ears.
Take them off after ten minutes.
Check for red marks either side of your nose or behind your ears. Faint marks are normal; deep indentations or soreness mean pressure that will become a headache by evening.
Frames and prescription
Your prescription limits your frame choice more than you expect
Frame and lens are not separate decisions, which is why we ask to see your prescription before you fall in love with something.
Strong short sight
Lenses are thick at the edges. Smaller frames and full rims hide that; large frames and rimless mounts expose it. A higher index helps, but frame size does more.
Strong long sight
Lenses are thick in the centre and magnify your eyes. Smaller frames again help, and an anti-reflective coating reduces the ring reflections that draw attention to lens thickness.
Progressives
Need vertical lens depth for the corridor. Very shallow, wide frames cut it short and make the reading zone cramped. If you want a shallow frame, we will tell you what it costs in comfort first.
High astigmatism
Lens edges thicken unevenly, so frame shape affects appearance more than usual. Rounder shapes tend to distribute it more kindly than sharply rectangular ones.
Rimless mounts
The lens is drilled and carries the structure, so it needs to be polycarbonate or a tough high index. Not suitable for very strong prescriptions.
Prism correction
Adds thickness on one edge. Full rim frames with reasonable depth handle it best. Worth mentioning up front if your prescription includes it.
Bring the prescription, and your current glasses
The pair you are wearing tells us what has been working and what has not, which is often more useful than the prescription itself. Ten minutes in the shop settles most of what is on this page.
Come and try
Frames are worth trying on
No amount of measurement replaces seeing a frame on your own face. Walk in Monday to Saturday and take your time with it.