No more switching between your readers and sunglasses. Men's Rectangle Reading Sunglasses in Gunmetal with Smoke Lenses by Foster Grant - Braydon SunReaders® - +3.25 The bottom third has the highest strength (and the power you choose) for reading, the middle third has a slightly reduced magnification for computer use, and the top third has about half the strength of the bottom, for clarity when interacting with someone nearby (sitting across a desk, for example).