The Dry Eye Zone

Rebecca's Blog


Study: Review of serum drop studies

This is review is disappointing, but not altogether surprising.

For the record, the only part of this that I personally care about are the symptom trackers - because for those of us living with dry eye, that’s what matters most. Are these drops making people more comfortable in the long term?

There’s tons of anecdotal evidence that (1) it takes awhile before they help, for some people; (2) some types of patients are helped more than others - and science needs to figure out who! and (3) for some users, it’s less a medical treatment than a safe, tolerable alternative to polymer-based artificial tears to which they have allergies or have developed intolerance. To me, that all underscores the vital need to measure symptoms.

Which indicates a huge, gaping hole here - implicating the studies that were reviewed: Where are the LONG TERM SYMPTOM CHANGE data? That is, OSDI or SPEED or some other symptom survey, employed at intervals for up to twelve months. That’s what we need meta-analysis of… but if studies do not use the same outcome measures with any consistency, it just can’t be done. Sigh.

Last, a little bone to pick. All serum is not equal. It would have been nice to see something in the abstract or at any rate in some part of the publicly available materials indicating what concentration(s) were in the selected studies.

Serum eye drops for the treatment of ocular surface diseases: a systematic review and meta-analysis. Franchini et al, Blood Transfus. 2019 May;17(3):200-209.


The use of blood-derived eye drops for topical treatment of ocular surface diseases has progressively increased in recent years.


To evaluate the use of serum eye drops in ocular surface disorders, we performed a systematic search of the literature.


In this systematic review, we included 19 randomised controlled trials (RCTs) investigating the use of serum eye drops in 729 patients compared to controls. For the quantitative synthesis, we included only 10 RCTs conducted in patients with dry eye syndrome comparing autologous serum to artificial tears. At 2-6 weeks, no clear between-group differences in Schirmer test (MD 1.05; 95% CI: -0.17-2.26) and in fluorescein staining (MD -0.61; 95% CI: -1.50-0.28) were found (very low-quality evidence, down-graded for inconsistency, serious risk of biases, and serious imprecision). Slightly higher increase in tear film break-up time (TBUT) scores in autologous serum compared to control (MD 2.68; 95% CI: 1.33-4.03), and greater decrease in ocular surface disease index (OSDI) in autologous serum compared to control (MD -11.17; 95% CI: -16.58 - -5.77) were found (low quality evidence, down-graded for serious risk of bias, and for inconsistency). For the Schirmer test, fluorescein staining and TBUT, data were also available at additional follow-up timing (2-12 months): no clear between-group differences were found, and the quality of the evidence was graded as low/very-low.


In patients with dry eye syndrome, it is unclear whether or not the use of autologous serum compared to artificial tears increases Schirmer test and fluorescein staining scores at short-term and medium-/long-term follow up. Some benefit at short-term follow up for the outcome of TBUT and OSDI was observed, but the quality of the evidence was low.