D
- D-segment
- decentration
- depth perception
- design reference point
- differential light sensitivity, S
- differential luminance, DL
- digitally rounding focimeter
- dimensions of lens blanks or lenses
- dioptre
- dioptric power
- Direct ophthalmoscope
- dispersion
- display magnification
- display size
- distance cap
- Distance dependent ophthalmometer
- distance design reference point
- distance optical centre
- distance portion
- distance portion curve
- distance reference point
- distance visual point DVP
- diverging lens
- dividing line
distance portion curve
curvature of the distance portion of the segment side or progressive side, expressed as a surface power. NOTE1: The refractive index assumed in the measurement should be stated. NOTE2: For progressive-power lenses, measurment is carried out at the distance design reference point.