Discussion
Goblet cell metaplasia, non-SS, goblet cell metaplasia and cell density
This prospective study demonstrated that both AS and PRP eye drops are effective in improving corneal and conjunctival staining scores in primary SS DE with no significant difference at 4 and 12 weeks. In addition, TBUT improved in both groups, with no significant difference between them. Previous studies conducted on patients with non-SS DEThe tear film has epitheliotropic factors, such as growth factors, vitamins, electrolytes, and neuropeptides that are important in the growth and migration of epithelial cells for epithelial homeostasisSome studies reported that PRP contains a 1.5 times higher level of platelets than ASCompared with AS, PRP has a shorter preparation time using a commercial preparation kit because it does not require 2 h of clotting time. Although the preparation protocol of PRP varies according to the hospital, in our study, it was prepared with 3 min of centrifugation using a commercial preparation kit. Concerning the stability of PRP, Metheetrairut et al.The Schirmer I values did not improve in either group in our study. As the lacrimal gland is damaged in primary SS, we speculate that 12 weeks of AS or PRP treatment might not be sufficient to improve lacrimal gland function. The OSDI scores showed no improvement in both groups, but a previous studyThis study used only AS or PRP without anti-inflammatory eye drops. Therefore, we speculate that no combined use of anti-inflammatory eye drops might be the cause of no improvement in Schirmer I and OSDI symptom scores. Further studies comparing AS and PRP with concurrent use of anti-inflammatory eye drops in primary SS DE in a real-world setting are warranted.In this study, goblet cell metaplasia and cell density did not significantly change at 12 weeks from the baseline in the AS and PRP groups. Goblet cell metaplasia and a decrease in cell density are observed more frequently in SS DE than in non-SS DEThis study had a limitation in that a population consisting of only females was included, which may have resulted in selection bias. Further studies including participants of both sexes are warranted.In conclusion, both 20% AS and 20% PRP without anti-inflammatory eye drops are effective in improving ocular surface parameters in primary SS DE with no significant difference. Considering the shorter preparation time than that for AS, PRP eye drops might be a good alternative treatment for primary SS DE.