A Volk lens is a brand of diagnostic lens used with a slit lamp instrument which provides a bright focal source of light with a slit of variable width and height. It may be used to examine the tissues of the posterior segment of the eye in conjunction with a microscope (usually binocular) of variable magnification.
Classic VOLK diagnostic lenses include the following: 90D 78D 20D 60D 40D
Alternatives to VOLK lenses include lenses from Ocular inc and Ophthalmic instrument company
OICO lenses include the following: OICO 90D, OICO 78D, OICO 20D,
OICO diagnostic lenses
Ocular inc lenses include the following: 90D 78D 20D 54D
References
Volk lens Wikipedia(Text) CC BY-SA