<p>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.<br /> &nbsp;</p> <p>a.&nbsp;Lens index:&nbsp;Applying higher index lenses (1.60 index and above) can solve the problem of having a thick edge on a Negative lens,&nbsp;or a thick center&nbsp;on a Positive lens.&nbsp;</p> <p>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.<br /> &nbsp;</p> <p>b.&nbsp;Farsighted lenses:&nbsp;For farsighted wearers&nbsp;(there is &quot;+&quot; in front of SPH value) who want to select a higher index lens above 1.60,&nbsp;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.<br /> <br /> c.&nbsp;Small PD:&nbsp;For wearers that have a comparatively&nbsp;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&nbsp;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.</p>