Ready readers are plano-power magnifying spectacles from about +1.00 to +4.00 in +0.25 or +0.50 steps, sold without prescription through pharmacies, supermarkets, airports, petrol stations and online. Volumes are enormous and unit prices low; China's Wenzhou and Taizhou clusters and India's Agra make most of the world's supply.
Quality is the issue. Good readers have matched powers in both eyes, correct optical centres set at the standard reading PD, no prism, scratch-resistant lenses and hinges that survive use. Cheap readers fail on power accuracy and centration. EN 14139 in Europe sets the requirements; buyers should test samples on a lensmeter.
The market is growing with ageing populations and screen use; blue-light readers, folding readers, bifocal reading sunglasses and fashion readers at higher prices are the growth segments. For volume buyers the questions are power range, packaging, display stands and compliance for the destination market.