**3. Instruments used in capillaroscopy**

The instruments utilized for the study of nailfold capillaries have evolved over time, from stereomicroscope to the high magnification nailfold video capillaroscopy (NVC).

#### **3.1 Wide-field stereomicroscope**

It is the original technique utilized by Maricq et al. [1] and employs about 20× magnification for the evaluation of capillaries. It provides the panoramic view of nailfold capillaries and makes possible for the assessment of qualitative and quantitative parameters (**Figure 2a**). However, the instrument is expensive and nonportable, and access is limited to special interest groups.
