Overview
ISO 18490:2026 – Non-destructive testing - Evaluation of vision acuity of NDT personnel specifies the essential requirements and standardized procedures for assessing the vision acuity of personnel involved in non-destructive testing (NDT). This international standard, developed by ISO, addresses the quality requirements for vision test charts, test procedures, and acceptance levels relevant to near, far, and colour vision. The scope also includes guidance on personnel qualification for those administering these vision tests and additional informative annexes on grey scale perception and low contrast visual acuity.
Vision acuity assessment is indispensable in ensuring that NDT personnel can detect and accurately interpret indications during inspection activities. ISO 18490:2026 provides a harmonized framework to fulfill the specific vision requirements of NDT qualification standards, such as ISO 9712.
Key Topics
- Chart Quality and Marking:
- Only charts from recognized suppliers should be used to ensure consistent quality and resolution.
- Charts must be permanently marked with supplier details and reference to any relevant conformance.
- Test Procedure and Illumination:
- Tests for near, far, and colour vision must be conducted under controlled illumination, simulating conditions encountered during routine NDT work.
- Appropriate distances are specified for each type of vision test (e.g., 32/40 cm for near vision, 4 m for far vision).
- Vision Correction:
- Candidates must use the same eyewear as for typical NDT tasks. The use of non-tinted corrective lenses is permitted.
- Any reliance on correction must be documented in the test results.
- Qualification of Test Administrators:
- Vision acuity tests must be administered by a licensed physician, nurse, ophthalmologist, optometrist, or a trained professional approved by Level 3 NDT personnel.
- Acceptance Levels:
- Clear criteria are set for passing near vision (e.g., using Radner or Snellen charts), far vision (e.g., Landolt or Snellen charts), and colour vision (e.g., Ishihara plates).
- Additional guidance is given for trade tests if colour vision deficiencies are suspected.
- Annexes:
- Informative annexes cover topics such as grey scale perception, low contrast visual acuity, chart samples, and verification procedures for test administrators.
Applications
ISO 18490:2026 is crucial for organizations employing NDT personnel across industries such as aerospace, energy, manufacturing, and infrastructure. Typical practical applications include:
- Compliance with qualification standards: Fulfilling visual acuity requirements as a prerequisite for NDT personnel certification under ISO 9712 and similar frameworks.
- Routine and periodic vision evaluation: Ensuring ongoing capability of NDT personnel to perform critical inspections reliably under typical working conditions.
- Enhanced safety and inspection quality: By mandating standardized testing and acceptance criteria for vision acuity, the risk of oversight or misinterpretation during NDT inspections is minimized.
- Documentation and traceability: Structured reporting and attestation forms support compliance audits, personnel recordkeeping, and verification.
Related Standards
Organizations implementing ISO 18490:2026 should also be familiar with several related standards:
- ISO 9712: Non-destructive testing - Qualification and certification of NDT personnel
- ISO 7921: Ophthalmic optics and instruments - Near reading charts
- ISO 8596: Ophthalmic optics - Visual acuity testing - Standard and clinical optotypes and their presentation
- ASTM E3168: Standard practice for determining low-contrast visual acuity of radiographic interpreters
By following the requirements outlined in ISO 18490:2026, organizations can ensure consistent, objective evaluation of NDT personnel’s vision acuity, upholding both safety and inspection reliability across a range of industrial applications.
