Overview

This standard specifies the requirements and test methods for focimeters for measurement of spectacle lenses and contact lenses. It applies to focimeters designed for the measurement of vertex powers, cylinder axis, and prismatic power and prism base settings at a specified location of the lens in the area defined by the size of the focimeter aperture. The scope excludes instruments that can only measure the whole lens at once. The standard is applicable to instruments intended for routine use, for example at the optician or ophthalmologist and which are typically used to demonstrate conformity of spectacle lenses or contact lenses with the reference values provided for them, and compliance with the tolerances in accordance with the relevant International Standards. The standard does not cover focimeters with additional functions and/or higher precision requirements which may be necessary for special applications, for example during the manufacture of spectacle lenses. Part 2 of DIN EN ISO 8598 which is currently in preparation is intended to deal with test lenses for use during calibration of focimeters and to replace the currently valid standards DIN EN ISO 9342-1 and DIN EN ISO 9342-2. This standard is primarily directed at manufacturers and designers of the instruments concerned. In respect to DIN EN ISO 8598, extensive modifications have been made: For example, the requirements for the lens support and for the axis marker have been rendered more precise and the metrological requirements have been revised or supplemented by further requirements. New requirements also include environmental conditions during use of the instruments, their capability of measuring tinted lenses and the marking of instruments and information to be supplied by the manufacturer together with the instruments, amongst others. The International Standard ISO 8598-1 has been prepared by ISO/TC 172/SC 7 "Ophthalmic optics and instruments". The body responsible for the German standard DIN EN ISO 8598-1 is Working Committee NA 027-01-08 AA "Augenoptik" ("Ophthalmic optics") at DIN Standards Committee Optics and Precision Mechanics (NAFuO).

Document: references other documents

Document: referenced in other documents

Responsible national committee

NA 027-01-08 AA - Ophthalmic optics  

Responsible european committee

CEN/TC 170 - Ophthalmic optics  

Responsible international committee

ISO/TC 172/SC 7 - Ophthalmic optics and instruments