Before you start browsing frames, obtain an up-to-date prescription from your eye care professional. Key elements to be aware of include: 1. OD (Right Eye) and OS (Left Eye): Your prescription will contain specific values for each eye. Understanding these values is crucial for selecting the right lenses. 2. Sphere, Cylinder, and Axis: These parameters address nearsightedness (myopia), farsightedness (hyperopia), and astigmatism. Familiarize yourself with these terms to interpret your prescription accurately. 3. Pupillary Distance (PD): This measurement represents the distance between the centers of your pupils and is essential for accurate lens alignment. While some prescriptions include the PD, you may need to measure it yourself or ask your optician.