Evaluation of umbilical cord blood serum eye drops for severe dry eye in two distinct populations—Sjögren’s syndrome and mustard gas–induced ocular injury: Protocol for a pilot randomized clinical trial - Seyed Hashem Daryabari; Hossein Aghamollaei; Seyyed Morteza Hosseini Imeni; Masoud Rostami (PLoS ONE, 2025)