Ask someone what they paid for their glasses and they will tell you about the frame. Ask them why they stopped wearing them and the answer is almost always about something else. A pair of glasses is four decisions, and the visible one is not the one that usually goes wrong.
One: the frame, and what “good” means in one
A well-made frame holds its adjustment. That is the whole test. Hinges that do not loosen, acetate that has been properly cured so it does not go brittle, titanium that returns to shape rather than staying bent. You can feel it in the hand: a good frame flexes evenly and springs back. A poor one twists at one temple and stays twisted, which is why it slides down your nose by March.
Two: the lens, which is most of what you are looking through
The lens is the optical instrument. Material affects thickness and weight; the surface design affects how wide the clear area is and how much distortion sits at the edges; coatings affect reflections, scratching and cleaning. A modern varifocal surfaced to your measurements is a genuinely different object from a stock design, and the difference is most obvious in the parts of the lens you use without thinking.
Three: the measurements
- Pupillary distance, so the optical centres line up with your pupils
- Fitting height, which decides where the reading area of a varifocal begins
- Vertex distance — how far the lens sits from your eye, which changes the effective power
- Pantoscopic tilt, the angle the frame sits at relative to your face
- Wrap angle, which matters on anything curved
- And your working distances, measured with the thing you actually hold, at the desk you actually use
These are taken on your face, in the frame you have chosen. Taken from a photograph or averaged from a table, they are approximations — and an approximation in a single-vision reading pair is often survivable, while the same approximation in a varifocal is the reason someone tells us they “never got on with them”.
Four: the fit, which is not a one-off
Glasses are worn for fourteen hours a day and put down on bedside tables. They move. A fitting appointment when you collect them, and an adjustment whenever they need one, is what keeps the other three decisions true. This is ongoing work rather than a transaction, and it is free for as long as you have the glasses.
Where the money actually goes
People are often surprised that the lens can cost more than the frame. It frequently should. If you want to know what separates one lens from another, why some varifocal lenses cost more goes through it, and the hidden cost of cheap glasses covers the other end of it.
You choose a frame in ten minutes and look through the lenses for three years. It is worth knowing which of those decisions you are actually making.← Back to the Journal
