How Corridors Lengths Impact Patient Satisfaction

Corridor lengths can have an impact on your patient’s experience with their eyewear. The technology in many free form progressive lenses uses unique algorithms to determine the best corridor for each patient prescription. The question is: Is that always the best option? Let’s find out!

Download the Sales aid. Included are fitting height charts by lens design as well as ordering instructions.

Fixed vs. Variable

There really is no difference between fixed and variable corridor lengths. When you select a variable corridor length the algorithm determines which FIXED corridor to use. This corridor length is calculated based off the B measurement of the frame and the fitting height of the patient. The variable option should be used with a majority of patients as the algorithm will determine the best fixed corridor.

For HOYA lens designs, the corridor length is measured from the fitting height to 100% of the add power. Corridor length options range from 11mm to 17mm depending on the lens design.  The length of the corridor has an impact on the amount of distortion found in the progressive design.

Short vs. Long

In the early 2000’s smaller frame designs became popular. This necessitated the need for a shorter corridor.  Frame designs today tend to be larger and a longer corridor is an option. There are pros and cons to a short corridor. The downside to a short corridor is more distortion, the benefit is the ability to quickly find the reading zone and they can select wider variety of frame size. The downside of a long corridor is the reading tends to be lower than the patient’s natural posture and harder to find, and the benefit is less distortion.

Pro Tip: Using a centration chart to verify all the zones are within the lens shape will dramatically reduce redos.

Why would you choose one corridor over another?

Example #1Patients changing from small frame style to large frame style:

The patient who wore a smaller corridor with their previous pair of glasses may struggle with a longer corridor pair of glasses as the reading zone will not be where they are used to finding it.

This patient will prefer a shorter corridor that closely resembles their previous pair.

Example #2 Patient is purchasing multiple pairs:

The patient will prefer both pairs of glasses to have the same corridor. This will allow the patient to change from one pair of glasses to the other without having to adapt to a different corridor each time.

The optician should match the corridors in each pair of glasses by choosing the shorter of the two options. 

Example #3 Patients who are avid computer users but only want one pair of glasses:

Lengthening the corridor will provide a larger intermediate zone with less distortion. Be careful when lengthening the corridor that you do not push the reding zone below the edge of the lens and outside the frame.