Because most frame shapes already sit well on an oval face, sunglasses shopping here comes down to personal style and lens coverage rather than corrective shape choices.
The Styling Principle
Oval faces have the most structural balance of any shape, so the styling goal is preservation, not correction — most cuts, frames, and silhouettes already sit well on this shape. The main risk is choosing something so voluminous or so severe that it manufactures an imbalance that wasn't there to begin with. Because most frame shapes already sit well on an oval face, sunglasses shopping here comes down to personal style and lens coverage rather than corrective shape choices.
Sizing
As with prescription frames, sunglasses width should roughly match your face's widest measurement — for a oval face that means sizing relative to cheekbones.