Guide
Choosing Volk Lenses
Which lenses a practice actually needs, what the numbers on them mean, and where the money is worth spending.
Which lenses a practice actually needs, what the numbers on them mean, and where the money is worth spending.
Every condensing lens trades one for the other. A higher dioptric power gives you more field and less magnification; a lower power gives you a tighter, larger view. That single relationship explains most of the catalog. A 90D shows you more of the retina at lower magnification and gets through a smaller pupil. A 78D gives you a bigger, more detailed view of the disc and macula with better stereopsis. Neither is the better lens. They are two jobs.
The series matters too. Volk's Classic designs established the double-aspheric standard; the Super series reworked the geometry for wider fields and better small-pupil performance; the Digital series adds higher-index glass and improved anti-reflective coatings, which shows most when you are photographing through the lens or working against reflections.
One general slit lamp lens. The workhorse for routine posterior segment examination. Most clinicians settle on something in the 90D class, or a wide-field Super or Digital lens when they want more periphery without giving up much magnification.
One high-magnification lens. For the optic nerve head and macula when detail matters: a 78D, or a 66D-class lens if you want 1.0× magnification so disc measurements need no scaling factor.
One BIO lens. For dilated peripheral examination, usually in the 20D to 28D range depending on how much periphery you cover and how much magnification you want.
A gonio lens. A four-mirror for dynamic indentation gonioscopy; a three-mirror if you also want peripheral retinal views through the same lens.
Buy for the exam you do most. Residents are often told to buy a full set. Practicing clinicians reach for the same two lenses most of the time. Start there and add deliberately.
Coatings earn their keep on photography. If you image through the slit lamp, the reflection control on the newer series is not a cosmetic difference.
Handle and case matter more than people expect. A lens that is comfortable to hold gets used; a lens without a decent case gets scratched.
Ask about your existing bench. If you already own a good general lens, the useful purchase is usually the complementary one rather than an upgrade to what you have.
We will suggest the one or two lenses that fill the gaps rather than quoting you a set.