By Dr. Mark Page · · 3 min read
Choosing frames is usually presented as a style exercise, and the style part is the easy part. The reason people end up disliking a pair they were excited about is almost always fit.
There is also an optical dimension that nobody mentions at the counter, and it matters more than the frame's appearance.
The three measurements that matter
- Eye size
- The width of each lens opening. Too wide and the frame extends past your face and slides. Too narrow and it pinches and looks compressed. The frame should be roughly as wide as the widest part of your face.
- Bridge width
- The gap between lenses that sits on your nose. This is the measurement that most often gets it wrong. Too wide and the frame slides down constantly. Too narrow and it perches too high and leaves marks.
- Temple length
- The arms. They should follow the side of your head and bend gently just past the ear, not press before it or dangle past it. Too short pushes the frame forward, too long lets it slide.
Why sliding glasses change your prescription
This is the connection people find genuinely surprising. A lens is optically correct only in a specific position relative to your eye.
When we make your lenses, we position the optical centres to line up with your pupils in the frame you chose, worn in your normal posture. If the frame then slides down your nose, your pupils are no longer looking through those centres. You are looking through a part of the lens that has a different effect.
For a single vision lens at a low prescription, the effect is small. For a strong prescription, and for any progressive, it is the difference between a lens that works and one you fight all day. It is one of the most common explanations for glasses that are correct on paper and wrong on the face.
Face shape advice, deflated
There is a great deal of rigid advice about face shapes and frames, most of it overstated. The one genuinely useful principle is that contrast tends to flatter: angular frames add definition to softer features, rounded or softly squared frames soften strong angular features.
Beyond that, proportion matters more than shape. The frame should be about as wide as the widest part of your face, the top should sit near your brow line, and your eyes should sit near the horizontal centre of the lens rather than high or low.
Everything else is preference, and preference is legitimate. If you love a frame that breaks every guideline and it fits, wear it.
What your prescription rules out
- Strong minus prescriptions produce thick edges, so a smaller full-rim frame keeps the lens looking and feeling better
- Strong plus prescriptions are thick in the centre and also do better in smaller frames
- Rimless and semi-rimless designs require lens material tough enough to be drilled, meaning polycarbonate or Trivex rather than standard plastic
- Progressives need vertical depth for the corridor. Very shallow frames physically cannot carry a full progression
- Wrapped frames need optical compensation so the prescription is accurate through the curvature
Why we measure before you browse
A wall of six hundred frames is not more choice, it is paralysis, and most of those frames were never going to fit your face.
We take your measurements first and identify which frames physically suit you and your prescription. Then you choose from that much smaller set. It is faster and it produces a better result, and it means we are not talking you out of something at the last moment.
Keeping the fit
Frames drift. They get pushed up, taken off with one hand, left in hot cars, and sat on. A frame that fitted perfectly in March may sit badly by September.
Adjustments, nose pads and screws are free here for the life of the glasses, with no appointment. If the fit feels off, walk in. It takes a few minutes and it restores the optics as well as the comfort.
The short version
- Three measurements decide whether a frame works: eye size, bridge width and temple length. Bridge width is the one most often wrong.
- A frame that slides down drops the lens optical centres below your pupils, which effectively changes your prescription.
- Face-shape advice is mostly overstated. Proportion matters more than shape, and preference is legitimate.
- Your prescription constrains frame choice more than most people expect, particularly for progressives, which need vertical depth.
- We measure before you browse, so everything you try on can actually work. It is faster and produces a better result.
- Adjustments, nose pads and screws are free here for the life of the glasses. If the fit drifts, walk in.
- If your budget forces a choice, spend on the lens rather than the frame. You look through the lens all day and at the frame only in a mirror.
- Most people genuinely need two pairs in this climate, and prescription sunglasses are protective equipment rather than an accessory.
Want the full detail?
Browse our frame collectionThis article is general educational information, not medical advice or a diagnosis, and it is not a substitute for an examination. If you are experiencing sudden vision loss, eye pain or an eye injury, contact us immediately or go to an emergency room.