Classic Indirect BIO Lenses

In 1956, aspheric ophthalmic lenses for subnormal vision were developed by Dr. David Volk. He found that an aspheric surface corrected the aberrations present in more common spherical lenses.

Several developments occurred with the aspheric lens designs through the years, delivering far supe-rior imaging for BIO examinations. In 1982 all Volk lenses for indirect ophthalmoscopy were redesigned with both surfaces aspheric, providing a substantial improvement in image quality.

The 20D and other Volk BIO lenses have been known as the industry standard for decades, and are still widely used in every corner of the world today.

Digital Series Indirect BIO Lenses

In the Volk spirit of improvement, our 3rd generation, ‘Digital Series’ BIO lenses were developed from the previous generation BIO lenses, in a similar fashion to the Digital Series slit lamp lenses. The goal: to deliver enhanced resolution imaging with the indirect ophthalmoscope.

Working with a high grade glass, we looked at all aspects of their double aspheric designs with ad-vanced computer modeling techniques. We realized improvements in all aspects of the BIO lens capa-bilities, ultimately delivering the best image quality attainable for indirect ophthalmic exams.

Macula Plus® 5.5




Pan retinal® 2.2



30D Small



Key benefits :

  • Low Dispersion glass delivers enhanced resolution
  • Reduced ring diameter and working distance facilitate lens manipulation
  • Advance A/R coating minimizes reflections and glare

Digital ClearMag

Digital ClearField