Rx spectacle lens standard: Do we have what we need?

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Since February 1 2010 the standard used in the UK for the verification of prescription spectacles has been BS EN ISO 21987:2009.1 This is a comprehensive and complex document, and the purpose of this article is to discuss the origins and purposes of lens standards, and to see if the current standard satisfies the needs of the modern ophthalmic practice.

The first published spectacle lens standard is believed to be a set of tolerances produced by the Shuron optical company in the USA in the 1940s. In the UK, the first standard was BS 2738, published in 1956. This document had been produced at the request of the then Ministry of Health, which needed a set of standards for the quality control of NHS spectacles. The BS 2738 mounted spectacle standard then evolved through a number of versions, the last being BS 2738-1:1998.