Frame Size and Fit Guide

Last updated: July 24, 2026

This guide explains common eyewear measurements and helps customers compare a Montivue Optics frame with glasses they already own.

It is informational and does not replace professional optical fitting or advice.

Understanding Frame Measurements

Eyewear is commonly described using several measurements in millimeters.

Lens width

The horizontal width of one lens at its widest point.

A larger lens width generally produces a wider overall appearance, although frame design also affects fit.

Bridge width

The distance between the two lenses at the part of the frame that rests around the nose.

Bridge design affects how high or low the glasses sit and whether they slide.

Temple length

The length of each arm from the hinge toward and around the ear.

Temple length affects how the frame reaches and rests behind the ears.

Lens height

The vertical height of the lens.

Lens height can affect the viewing area, appearance, and fit of multifocal-style lenses.

Total frame width

The full horizontal width from the outer edge of one side of the frame to the outer edge of the other.

Total frame width is one of the most useful measurements for judging whether a frame will feel narrow, regular, or wide.

Reading the Numbers on Existing Glasses

Many frames have three numbers printed inside a temple arm or near the bridge.

For example:

52 – 18 – 140

This commonly means:

• 52 mm lens width.
• 18 mm bridge width.
• 140 mm temple length.

Not every frame displays measurements in the same order, and total frame width may not be printed.

Comparing With Your Current Glasses

For the most reliable comparison:

1. Choose a pair of glasses that currently fits you well.
2. Check the numbers printed inside the frame.
3. Compare them with the measurements on the Montivue Optics product page.
4. Measure the total width with a millimeter ruler when necessary.
5. Consider whether your current frame feels narrow, comfortable, or wide.

A small difference may still fit comfortably because materials, hinges, bridge shape, and frame curvature affect fit.

Measuring Total Frame Width

Place the glasses on a flat surface.

Measure horizontally from the furthest outer edge on one side to the furthest outer edge on the other side.

Do not follow the curve of the frame. Measure in a straight line.

General Fit Categories

Product measurements may generally correspond to:

Narrow fit

Often more suitable for customers whose current frames feel best at a smaller total width.

Regular or medium fit

Designed to suit a broad range of average adult face widths.

Wide fit

Often more suitable for customers who find standard frames tight around the temples.

These descriptions are general. Face shape, bridge shape, frame material, and personal preference remain important.

Signs of a Suitable Fit

A frame generally fits well when:

• It does not create painful pressure on the temples.
• It does not slide excessively down the nose.
• The eyes sit reasonably close to the horizontal center of the lenses.
• The temples reach comfortably behind the ears.
• The eyelashes do not continually touch the lenses.
• The frame remains reasonably stable with normal head movement.
• The lower edge does not press uncomfortably against the cheeks.

Signs a Frame May Be Too Narrow

A frame may be too narrow when:

• The temples press outward strongly.
• The hinges appear stretched.
• Pressure develops near the temples.
• The frame leaves uncomfortable marks.
• The lenses appear too close together relative to the eyes.

Signs a Frame May Be Too Wide

A frame may be too wide when:

• It slides frequently.
• The temples angle inward significantly behind the ears.
• The frame moves during normal activity.
• The eyes appear unusually close to the inner edges of the lenses.
• The bridge cannot hold the frame securely.

Bridge Fit

Bridge fit depends on shape as well as measurement.

Two frames with the same bridge width can fit differently because one may have:

• Adjustable nose pads.
• A keyhole bridge.
• A saddle bridge.
• A flatter or more curved nose area.

Review product photographs and descriptions for bridge details.

Temple Fit

Temple arms should reach the ears without excessive pressure.

Some lightweight frames are flexible, but they should not need to be forced widely apart to fit.

Do not bend or heat a frame unless the product instructions specifically permit adjustment.

Lens Strength Is Separate From Frame Size

Lens strength or diopter does not determine physical frame size.

Choose:

• Frame measurements based on face and current-glasses fit.
• Lens strength based on your visual needs and appropriate professional guidance.

Ready-Made Multifocal-Style Eyewear

For ready-made multifocal-style products, head and eye position may affect which part of the lens is used.

An adaptation period may occur. However, persistent discomfort, dizziness, headaches, double vision, or significant visual difficulty should not be ignored.

Stop use and consult a qualified eye-care professional when appropriate.

Measurement Tolerances

Small measurement variations may occur because of manufacturing and measuring methods.

Product dimensions should be treated as approximate unless expressly stated otherwise.

Fit Assistance

For fit-related questions, email:

support@montivueoptics.com

Include the product name and, when possible, the measurements of a frame that already fits you well.