In clinical practice the Flammer syndrome can be diagnosed with some certainty based on the patient’s history (such as cold hands or feet) and clinical examinations (such as 24-h blood pressure monitoring).
If necessary, the diagnosis can then be substantiated by more specific examinations such as 

  • nailfold capillaroscopy with a cold provocation test
  • dynamic retinal vessel analysis with flicker-light stimulation 
  • quantification of gene expression in lymphocyte
  • measurement of retinal venous pressure
  • quantification of Endothelin plasma level

Examples of more specific examinations are capillary microscopy (top) and Dynamic Retinal Vessel Analysis, DVA (bottom).

Taken from Konieczka et al.
Primäre vaskuläre Dysregulation und Glaukom, Z. prakt. Augenheilkd. 34: 207 – 215 (2013)