01 · SIZE
Large frames require a larger lens area
Sunglass frames are often wider and taller than everyday optical frames. In minus prescriptions, edge thickness tends to increase farther from the optical centre, so frame size can materially affect the finished lens.
The higher the prescription, the more important it becomes to consider required lens diameter rather than design size alone.
A large prescription sunglass frame affects more than the diameter of the blank that must be ordered. In minus lenses, edge thickness tends to increase farther from the required optical reference point, so a larger finished shape can retain more of that thick peripheral region. Prescription strength and frame size should therefore be considered together.
02 · EYE POSITION
Eye position matters even when frame size is the same
If the pupil sits far from the geometric centre of the frame, more decentration and a larger effective diameter may be required.
The frame should therefore be evaluated by where the pupil actually sits inside it, not by PD as a number alone.
Eye position matters even within the same frame. If the pupil lies far from the geometric centre of the lens shape, more decentration and potentially a larger effective blank diameter may be needed to place the required optical reference correctly. Frame dimensions alone are not enough to predict finished thickness without monocular PD and actual eye position.
03 · WEIGHT
More thickness can also change weight and fit
A large frame combined with a stronger prescription can make the front of the sunglasses heavier than expected.
As front weight increases, bridge support and temple balance become part of the lens decision rather than a separate fitting issue.
The finished sunglass must also remain stable on the face. Large frames with heavier prescription lenses can increase front weight and sliding, which then changes the relationship between the pupil and the measured lens position. Frame size, curve, eye position, lens thickness and fitting all belong to the same prescription-sunglass system.
04 · CURVE
Frame curvature must be checked
Wraparound sunglass frames place the lens at a larger angle in front of the eyes than ordinary optical frames. Prescription lenses may need different design and compensation conditions.
Confirm that an appropriate prescription lens design is available for the selected frame.
Sunglasses often use more base curve or wrap than ordinary spectacles. When a powered lens is positioned at a large face-form angle, effective sphere, cylinder and prism along the line of sight can change. Some designs therefore use wearing-position compensation, and not every high-wrap frame is equally suitable for every prescription.
05 · TINT
Choose tint and colour after confirming the optical conditions
First confirm prescription, frame size, eye position, curvature and lens-design feasibility. Then choose tint, polarization or mirror options.
This avoids selecting a colour first only to discover later that the desired lens construction is not practical in that frame.
Availability can also limit the combination. Certain high-curve blanks, polarization, photochromic technology or mirror options may not be offered in every prescription range or refractive index, and stronger prescriptions can restrict usable diameter and finished thickness. It is safer to choose frame and lens together than to commit to the frame first and ask whether the lens is possible afterward.
GLANOS LENS CHECK
A practical prescription-sunglass order
Confirm the optical correction and lens requirements.
Check PD and actual pupil location in the frame.
Estimate required diameter, thickness and weight.
Confirm face-form angle and suitable lens design.
Add tint, polarization and mirror last.
CAUTION
Frame choice and lens choice are difficult to separate in prescription sunglasses
This is especially important with high prescriptions, oversized frames and high-wrap designs.
GLANOS EYEWEAR
Eyewear comfort has reasons.
Prescription sunglasses · Frame size · Decentration · Thickness · Wrap