Overview
ISO 12866:1999 - "Ophthalmic instruments - Perimeters" defines performance requirements and type test methods for perimeters used to assess differential light sensitivity across the visual field by subjective detection of test stimuli. The standard covers both static perimeters (stationary stimuli) and kinetic perimeters (moving stimuli), specifies how luminance and stimulus parameters are reported (in cd/m2 and perimetric decibels), and sets requirements for instrument documentation and marking. It is a device-level standard and does not prescribe clinical test strategies or psychophysical protocols.
Key topics and technical requirements
- Scope and definitions: Clear terminology for visual field, monocular/binocular fields, central vs peripheral field, stimulus luminance, differential luminance, contrast, and the perimetric decibel scale.
- Performance tolerances: Requirements for background luminance and stimulus parameters with specified tolerances (see Table 1). Example position tolerances: within 0.5° for stimuli within 10° of centre, 1° for 10°–30°, and 2° beyond 30°.
- Luminance and units: Background and stimulus luminances must be specified in candela per square metre (cd/m2); spectral distributions must be provided by the manufacturer.
- Stimulus specification: Test stimulus sizes (including Goldmann stimulus sizes described in Annex A), shapes, durations and patterns; conversion of physical size to solid angle for verification.
- Kinetic vs static perimeters: Kinetic perimeters must provide smooth, continuous stimulus movement (or smooth manual control). Static perimeters must specify temporal characteristics and the complete set of test locations (polar or Cartesian coordinates referenced to the eye’s entrance pupil; see Annex B).
- Type test methods: Procedures to verify background luminance, stimulus luminance, location, size, shape and duration (see Clause 5 and Table 4 for example test locations and dB steps).
- Usability and traceability: Requirements for head positioning, optical correction provision, fixation monitoring, measurement at fixation, result quantification per test location, and required data to appear on test records and marking.
Applications and who uses this standard
ISO 12866 is intended for:
- Manufacturers and designers of perimeters (projection and fixed-stimulus devices) to guide product specification, quality control and type testing.
- Medical device test laboratories performing type approval, conformity assessment and performance verification.
- Regulatory and procurement teams evaluating perimetric equipment for clinical use or certification.
- R&D teams developing new perimetry hardware or optical systems that must meet international performance benchmarks.
Keywords: ISO 12866, ophthalmic instruments, perimeters, perimetry, visual field testing, stimulus luminance, background luminance, Goldmann stimulus, perimetric decibel.
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