Nailfold and retinal microcirculation have been showed to linked in this study of healthy subjects.
Fashionable nails and eyes? The health of the capillaries (tiny blood vessels) in your nail fold is indicative of the health of the blood vessels in your eyes.
The status of microcirculation is important in many diseases. The condition of the nailfold capillaries can be assessed using nailfold capillaroscopy (NFC), which is sensitive and non-invasive and is useful in the evaluation of diabetes, schizophrenia, and rheumatologic conditions. Retinal microcirculation is also important in ocular diseases, such as in glaucoma, and can be evaluated non-invasively with the use of optical coherence tomography angiography (OCTA).
In this cross-sectional study, the association between nailfold and retinal circulation was evaluated in healthy subjects. These patients did not have any systematic or ocular diseases. Using OCTA, the following parameters were analyzed: peripapillary retinal nerve fiber layer (RNFL) thickness, vessel density (VD) of radial peripapillary capillaries (RPCs), and superficial capillary VD in the macular area. Meanwhile, NFC was done to analyze the following parameters: capillary density, avascular zones, extent of dilated capillaries, and hemorrhages on the the fourth digit of the non-dominant hand.
After multivariate analysis and adjusting for systemic factors, results showed that there was a significant direct relationship between RNFL thickness and nailfold capillary density. In addition, RNFL thickness and RPCs VD were inversely correlated with avascular zones in the nail folds, as was the parafoveal superficial VD with nailfold capillary dilation.
The results of this study showed that in healthy subjects, a lower capillary density in the nailfold and other abnormalities are associated with decreased RNFL thickness and retinal vessel density. Though the physiologic mechanisms underlying the healthy maintenance of the capillary endothelium in the nails and in the eyes are uncertain, the study points to the possibility of using both NFC and OCTA to identify risk factors in the development and to earlier diagnose diseases that have a microvascular component.
It should be noted that the researchers have specified the irreplaceability of NFC with OCTA and vice-versa, as the nailfold capillary is affected by external factors such as trauma and temperature and OCTA is thought to be more subjective. They recommend further longitudinal studies assessing the relationship between nailfold and retinal microcirculation to further examine the clinical use of these findings.
Tian, J., Xie, Y., Li, M., Oatts, J., Han, Y., & Yang, Y. et al. (2020). The Relationship Between Nailfold Microcirculation and Retinal Microcirculation in Healthy Subjects. Frontiers in Physiology, 11. doi: 10.3389/fphys.2020.00880