ASDA has launched an in-store advertising campaign to support its growing chain of Wal-Mart vision centres. But part of the advertisements will be obscured to comply with Government legislation that prevents opticians from comparing prices with other retailers.

With plans to open 50 vision centres by the end of the year, Asda is keen to give customers a clear view of what they are paying.

Optical business director David Miles said he is disappointed that prices are being wrapped in a veil of secrecy.