Several studies found that 50–100% serum eye drops provided greater benefits without inducing detrimental effects on the corneal epithelial healing. This study assessed the efficacy of undiluted serum eye drops for the treatment of persistent corneal epithelial defects (PED). A total of 109 eyes received 100% serum eye drops for PED were recruited into this study. The data were compared with an historical control group of 79 eyes with PED who received conventional treatments from 2006–2011 at the same institution. Main outcome measures were complete healing of PED and incidence of adverse events. No significant difference in demographics between the 2 groups was noted. The success rate of the treatment and control groups were 87.16% (95% CI 0.79–0.93) and 69.62% (95% CI 0.59–0.80) (P = 0.001), respectively. The median time to complete epithelialization was 14 days (95% CI 12–21) in the treatment group and 28 days (95% CI 21–59) in the control group (P = 0.001). Serum treatment, primary diagnosis of non-limbal stem cell deficiency etiology, and prior contact lens wear significantly correlated with the corneal re-epithelialization. There were no serious side effects encountered during the study period. In conclusion, undiluted serum therapy is effective and safe for treating PED.

Persistent corneal epithelial defects (PED) have been defined as an epithelial defect that does not heal within the expected time frame despite conventional treatment, which is usually described as 2 weeks in the literature1,2,3,4. Although PED are uncommon, they may lead to corneal inflammation, infection, scarring, melting, and even perforation5. PED can be a consequence of numerous diseases, including severe dry eye, limbal stem cell deficiency (LSCD), neurotrophic keratitis, exposure keratopathy, and post-infectious corneal ulceration, which are intractable problems and occasionally cannot be directly managed3,6. Therefore, a variety of standard therapies consisting of aggressive lubrication with preservative-free artificial tears, bandage soft contact lenses, pressure patching, epithelial debridement, and tarsorrhaphy have been used in an attempt to heal PED2. Nonetheless, some PED fail to resolve with these first-line treatments in an orderly and timely manner.

Human serum eye drops not only function as a natural preservative-free lubricant, but also supply epitheliotrophic factors and essential substances for the recovery of a damaged epithelium, potentially making it an excellent tear substitute6,7,8,9. Previous studies have proved the efficacy of a 20% solution in the treatment of PED, with 60–70% of eyes healing completely within 4 weeks3,10,11. This 1:5 dilution is empirically used to decrease the concentration of TGF-β, which is a pro-inflammatory factor, to physiologic tear levels12,13,14. Nevertheless, dilution could in turn reduce the concentration of other beneficial factors, particularly epidermal growth factor (EGF) and fibronectin. With the optimized manufacturing protocol, the serum and tear concentration of TGF-β are supposed to be equivalent and dilution may not be necessitated15. Recently, several studies found that higher concentrations (50–100%) seemed to provide greater benefits without inducing detrimental effects on the corneal epithelial healing5,16,17,18,19,20,21,22.

The purpose of this study was to evaluate the efficacy and safety of 100% serum eye drops for the treatment of PED not related to ocular surgery.