Umbilical Cord Mesenchymal Stem Cell-derived Small Extracellular Vesicles

This clinical trial aims to preliminarily evaluate the safety and efficacy of human umbilical cord mesenchymal stem cell small extracellular vesicle eye drops in patients with dry eye disease. 1. Human mesenchymal stem cell small extracellular vesicle eye drops: Administer one drop each time, 4 times daily, for a treatment duration of 4 weeks. 2. During treatment, subjects will be followed up and undergo examinations and related tests weekly. 3. After completion of treatment, follow-up visits will be conducted every 2 weeks for a total of 2 visits. 4. Subsequently, subjects will enter a long-term follow-up period, with follow-up assessments at 3 months and 6 months to observe longer-term safety and efficacy. 5. Subjects shall record medication usage and any possible adverse reactions.