Tilt & Wrap

Next, let's review some of the basic frame measurements that you need to understand in order to properly fit your patient for their new glasses. On the temple of most frames, no matter if they're plastic or metal, you'll have information printed on the inside of those temples. Usually these numbers come in three segments. The first being the eye size or a measurement of the frame. The second one being the bridge measurement of the frame and the third being the length of the temple in millimeters as well.

Usually you'll also have the name of the frame and then, in this case, there's also a 5001 which represents the color code for this frame. On plastic frames, you can also look for some of this information on the bridge or on the bottom side of thicker temples.

Also, on frames, we have to be able to measure tilt when it's on our patients’ glasses. Tilt is either pantoscopic or retroscopic. Pantoscopic tilt is the correct type of tilt on glasses, which means like we can see here, the top of the lens sticks out farther than the bottom of the lens. This also matches the natural curvature of the human face. Retroscopic tilt would be the exact opposite, like this, where we have the bottom of the lens sticking out farther than the top. Retroscopic tilt is never acceptable on your patients’ glasses. Usually this happens if someone sits or steps on their own glasses and needs them adjusted. It's also important to understand that as we add pantoscopic tilt to a multifocal lens design, it will enable our patient to use the reading portion of the lens easier, giving them better viewing through those lenses.

The frame wrap itself is the measurement in angle in degrees from the outside of both edges of the frame before the temples start. This can be measured a number of different ways but it’s important to understand that as we induce more wrap in a frame, it will change the way our patient sees and if there is too much wrap, it will actually produce a fisheye effect in your patients lenses.