We have read with great interest the article by Than et al1 regarding the use of fingerprick autologous blood (FAB) as an alternative treatment for dry eye syndrome (DES). Sixteen patients diagnosed with DES were treated with FAB, 11 of whom had Sjögren syndrome, obtaining good results for the different clinical variables evaluated. The treatment dosage was four times daily for eight weeks.

We commend the authors’ search of a low-cost and readily accessible treatment for this type of syndrome. At the same time, we would like to offer some commentaries and additional perspectives to the study.1

First, our experience is that, in order to achieve optimal therapeutic effects, it would be recommended that the concentrations of platelets and growth factors would be greater than those obtained in whole blood. A good example of that is platelet-rich plasma (PRP),2 a therapy in which platelets are concentrated in a volume of plasma. Furthermore, we speculate that if platelet activation is not completed in FAB, the amount of platelet-derived growth factors would be lower than even autologous serum (AS).

Second, the authors should clarify whether there is platelet activation in the ocular surface, or whether it does not always occur, for example due to the clearance of FAB. The authors state that clots are observed in some patients, but this should be generalized so that the method is reproducible. Recent studies carried out on ocular surface cells show that the biological activity of non-activated PRP is lower than AS or other activated PRPs, such as plasma rich in growth factors (PRGF).3

Third, it is important to highlight that most of the patients (11/16) had been diagnosed with Sjögren syndrome, a long-term autoimmune disease in which the already exacerbated inflammatory component of DES is accentuated.4 An interesting approach for these cases might be to perform an inactivation protocol of immune components in the eye drops, preserving most of the biologically active molecules while reducing immunoglobulin content and complement activity.5

Last but not least, there are other issues to be considered, including the drawback of not using a standardized ready-to-use product, the large amount of fingerpricks delivered (448 fingerpricks in 8 weeks), and the variability of capillary blood.6

We strongly encourage the authors to further deepen research in the FAB mechanisms of action and product composition in order to optimize the treatment and improve the quality of life of DES patients, thus offering a fully characterized product.