Differentiation between primary and secondary Raynaud's phenomenon: a prospective study comparing nailfold capillaroscopy using an ophthalmoscope or stereomicroscope

Background-Nailfold capillary microscopy is a routine procedure in the inve stigation of patients with Raynaud's phenomenon (RP). As a standard method, nailfold capillary morphology is inspected with a stereomicroscope to look for capillary abnormalities such as giant loops, avascular areas, and bush y capillaries, which have all been found to be associated with certain conn ective tissue diseases. Aim-To investigate prospectively whether nailfold capillary inspection usin g an ophthalmoscope is of equivalent diagnostic value to standard nailfold capillary microscopy. Method-All the fingers of 26 patients with RP were examined in a blinded fa shion and compared with the final diagnosis one month later. Results-All giant loops, large avascular areas, and bushy capillaries were identified by both methods. The correlation for moderate avascular areas an d crossed capillaries was 0.93 and 0.955 respectively. The correlation for minor abnormalities that do not contribute to the differentiation between p rimary and secondary RP was 0.837 and 0.861 respectively. All patients were classified identically by the two methods. Conclusion-For the evaluation of patients with RP, nailfold capillary morph ology can reliably be assessed with an ophthalmoscope.