During slit lamp biomicroscopy after the broad exam, which setup is used?

• A. Small circle, high light intensity, 4x magnification
• B. Large circle, lower light intensity, 10x magnification
• C. Large circle, high light intensity, 16x magnification
• D. Small circle, low light intensity, 20x magnification

Answer: (B)

When performing slit lamp biomicroscopy after the broad survey, you want to keep a wide field of view while keeping illumination gentle to avoid glare and discomfort. Using a large aperture (large circle) floods the anterior segment with light across a broad area, and lowering the light intensity reduces glare and helps the horse tolerate the exam. A moderate magnification, around 10x, provides enough detail to assess the corneal surface, anterior chamber, and tear film while still keeping a useful panoramic view of the structures. This setup supports efficient screening for abnormalities and lets you spot regions that may require closer inspection with higher magnification or a narrower beam. In contrast, a small circle with high light or very high magnification would narrow the field or increase glare, making broad survey more challenging.