This part of BS 2738 specifies, with reference to the prescription order (see note 2), tolerances for properties of mounted spectacle lenses.
This standard is not applicable to the transmission properties of tinted, coated or otherwise treated lenses nor to the material from which the lens is manufactured.
NOTE 1 Ophthalmic lens materials are specified in BS 3062 (to be replaced by ISO 8980-3). BS 7394-2 specifies requirements for glazing and lens robustness.
Recommendations regarding other characteristics of spectacle lenses that are related to tolerances, but are subjective and therefore cannot be specified, are given in annex A.
NOTE 2 It is assumed that the prescription order conforms to BS 2738-3.