Frame Selection Tips
On a high plus lens, care must be taken in selecting a proper frame. There are three guidelines that we recommend following in frame selection.
- Frame PD is within 4 mm of PD. Minimizing decentration is important with high plus RX’s. Too much decentration causes unnecessary nasal thickness, and it serves no purpose.
- Frame B measurement is greater than 70% of the A measurement. On this type of RX, a very narrow frame accentuates the thickness at the top and bottom of the frame.
- Frame doesn’t have sharp corners. The corners create an area with drastic thickness changes on the finished glasses, making the lenses look thicker. An oval or round shape is preferable.
Is the patient monocular?
If the patient only has one good eye, consider putting the lens on center (disregard the PD). Often, the compromise in optics is minuscule compared to the aesthetic benefit.
Importance of Lens Curvature
We can make some beautiful high-plus lenses using the shapes outlined below. To do this, we change the lens curves through a process called freeform lenticularization. Some patients are very sensitive to these changes in curvature. If you have a patient who you feel would be sensitive to these changes, we wouldn’t recommend straying from their current eyeglass lens design.
Shape #10: Standard
Fixed front and back curve, no lenticularization or asphericity.
Shape #11: Lenticular
A high base curve “bowl” on a flatter carrier lens. Can be done free-form or using standard semi-finished lenses.
A free-form version of aspheric supermodular cataract lenses
A free-form backside aspheric lens. Best for lenses where the front side of the lens cannot be altered(polarized lenses, Transitions)
2 Side Supermodular
Free-form aspheric curves cut into both sides of the lens. This is the thinnest lens design available
A free-form aspheric lens optimized for wrap sunglass frames