M
- Magnification
- Magnification of photography
- magnifier
- main beam
- main lens
- major portion
- major reference point
- Manufacturer
- margin
- matching lens
- mean reflectance
- mean transmittance in the ultraviolet A spectrum TUVA
- measured IOP
- measured power
- meniscus lens
- meridian of a lens
- meridian of a surface
- meridional power
- metal frame
- mineral glass
- minus-power lens
- monocular aid
- monocular field
- Monocular indirect ophthalmoscope
- monocular pupillary distance
- multifocal lens
- multifocal semifinished lens blank
minus-power lens
Lens which causes parallel incident light to diverge from a virtual focus.