: If your eyes require different strengths (e.g., +2.00 for the right and +1.50 for the left), look for sites like RX Safety that allow for "single vision" customization rather than fixed OTC powers. 2. Essential Measurements for Fit

: Many retailers like Warby Parker and Readers.com offer printable diopter charts. You must print these at 100% scale—using them on a screen will result in an inaccurate reading.

Reading glasses use magnification power measured in , typically ranging from +0.25 to +4.00 .