R
- Radiance L
- reading cap
- reading portion
- reduce-aperture trial case lens
- reduced aperture trial frame
- reduced-aperture lens
- Reference distance
- reference IOP
- Reference plane
- reference seeing distance (RSD)
- reference wavelength
- refracting angle
- refracting edge
- refractive index
- Refractor head
- relative distance magnification
- relative visual attenuation coefficient
- resolution
- resolving power of the fundus camera
- retinal hazard limit
- Retinoscope
- reverse polarity system
- round segment
reference wavelength
The wavelengths specified in ISO 7944. NOTE 1: For the purpose of this International Standard, the reference wavelengths are either the green mercury line (le=546.07nm) or the yellow helium line (ld=587,56nm). NOTE 2: The reference wavelength for which the test lenses are calibrated should be stated.