EN ISO 11380:1996

Overview

EN ISO 11380:1996 is an international standard that specifies the characteristics of formers used in edging machines for ophthalmic optics. Formers are tools designed to shape lenses accurately so they fit into spectacle frames. This standard is issued by CEN and aligns with ISO 11380:1994, ensuring global consistency in the production and quality of lens formers. It focuses only on formers used for edging lenses and excludes those for supplementary lens treatments such as facetting.

By adhering to EN ISO 11380, manufacturers and optical laboratories can ensure that lenses are edged precisely, improving the fit, comfort, and aesthetics of eyeglasses.

Key Topics

• Scope and Application
  The standard applies specifically to formers used to edge spectacle lenses for frame insertion. It defines the dimensional and marking requirements for two types of formers:

  • Lens Size Formers: Match the size and shape of the finished lenses.
  • Aperture Size Formers: Smaller than lenses by the nominal bevel size, matching the mounting aperture in the frame.

• Dimensional Requirements

  • Maximum tolerance of 0.2 mm difference between two formers of identical nominal size and shape.
  • Materials used for formers must be dimensionally stable to maintain precision.
  • Standardized hole systems and locating marks facilitate alignment within edging machines.

• Marking and Identification
  Each former must be clearly marked with:

  • Manufacturer's or supplier’s identification
  • Model identification
  • The letter "N" combined with a boxing symbol to indicate the nasal (inner) side of the former
  • Lens size in millimeters (for lens size formers) or with the addition of "aperture size" for aperture size formers
    Optional markings include the centreline and vertical axis for precise orientation, with strict tolerances on angular deviation.

• Technical Committee and Standardization Process
  Developed by ISO Technical Committee TC 172, Subcommittee SC 8 on Ophthalmic Optics, the standard benefits from expert consensus and international voting procedures to guarantee robustness.

Applications

• Optical Lens Manufacturing
  Formers defined by EN ISO 11380 are integral to edging machines that cut lenses to fit spectacle frames perfectly, ensuring comfort and optical performance.

• Quality Control
  Optical laboratories use this standard to verify the conformity of formers, maintaining consistency across batches and preventing lens fitting errors.

• Compatibility and Interchangeability
  Standardized formers facilitate the compatibility of edging equipment and lenses worldwide, helping manufacturers meet international quality expectations.

• Customization and Frame Variants
  Flexibility in former types (lens size and aperture size) caters to diverse spectacle frame sizes and styles, supporting tailored eyewear solutions.

Related Standards

• ISO 8980 Series – Ophthalmic Optics
  Covers test methods for optical properties and quality requirements of spectacle lenses.

• EN ISO 13666 – Ophthalmic Optics – Frames
  Specifies dimensions and marking for spectacle frames, complementing formers used for lens edging.

• ISO 17590 – Ophthalmic Optics – Reference Eyeglass
  Provides calibration standards which support lens and frame fitting accuracy.

Summary

EN ISO 11380:1996 plays a crucial role in the ophthalmic optics industry by standardizing formers used in edging machines. It ensures that lenses are edged with tight tolerances and marked clearly for easy identification and orientation. This results in better fitting spectacle lenses, improved manufacturing efficiency, and global interchangeability. Optical labs and manufacturers adopting this standard can improve product quality, reduce errors, and enhance customer satisfaction.

Keywords: EN ISO 11380, ophthalmic optics, lens formers, edging machines, spectacle lenses, optical standards, lens edging, aperture size formers, lens size formers, optical manufacturing, spectacle frame fit, optical instrument standards.