When purchasing single vision eyeglasses, wearers with higher prescription strength should be aware that large frame with a wider lens is not recommended, instead a smaller and narrower lens width will contribute to a thinner edge, lighter weight and greater comfort. Besides, a metal frame with a thin rim cannot hide the lens edge thickness as the same as a plastic frame, so the shorter and narrow plastic frame is recommended.
a. Lens index: Applying higher index lenses (1.60 index and above) can solve the problem of having a thick edge on a Negative lens, or a thick center on a Positive lens. Combining a higher index lens with an aspheric shape results in a lens which is noticeably thinner and lighter, bringing better vision, and a more comfortable wearing experience.
b. Farsighted lenses: For farsighted wearers (there is "+" in front of SPH value) who want to select a higher index lens above 1.60, please note, the maximum size of a high index positive lens is relatively small (just 55mm), so we recommend that customers choose a frame no wider than 50mm.
c. Small PD: For wearers that have a comparatively small PD (the distance between your pupils is less than 58mm), please pay more attention to the total width of the frame as a larger frame may not match your PD. A smaller frame with a lens width of 50mm or lower should be considered as the first choice in order to ensure the accuracy of your prescription.