When it comes to helping patients select frames that will be appropriate for their individual features and lens needs, it must not be underestimated how important proper bridge fit is to the overall comfort and performance of the glasses you will be designing with your patient. I’ve often heard that nearly 80% of the overall fit of the glasses happens at the bridge (and I don’t have the proper source to cite here, but in my personal observations, I’d say this is an accurate statement). If you have a poor bridge fit, it shifts the additional work of keeping the glasses in place to the temples and temple adjustment. This often creates a sore ear scenario, and an unhappy patient.

In Part 1, I introduced angle Kappa, the angle between the pupillary axis and the visual axis, as a reason for patient dissatisfaction with PALs.  Part 2 addresses why angle Kappa is important.

I was dispensing a pair of glasses to a patient I hadn’t seen for the initial fit.  As I leaned in to place the glasses on his face he said, “Now, don’t get scared.” In the split second between that statement and his next, I hesitated and wondered what was going to happen. It’s amazing what you can think of in a very short period of time! Would he bite? Have a seizure? Faint? It was a combination of relief and compassion when the patient told me he had a prosthetic nose. His nose had been removed due to cancer and replaced by a latex form. I had to look closely at his bridge to see the very fine line of the prosthesis.