A Randomized Controlled Trial of 20% Platelet-Rich Plasma versus 50% Platelet-Poor Plasma Eye Drops for Moderate-to-Severe Dry Eye Disease

INTERVENTION: Experimental group:20% Platelet‐Rich Plasma eye drops for patients with moderate‐to‐severe dry eye disease;Control group:50% platelet‐poor plasma eye drops for patients with moderate‐to‐severe dry eye disease; CONDITION: Dry Eye Syndrome PRIMARY OUTCOME: Total corneal fluorescein staining score (tCFS); SECONDARY OUTCOME: Zonal Corneal Fluorescein Staining Score;Conjunctival Hyperemia Score;Individual core ocular surface symptoms and Visual Analog Scale (VAS) scores;Fundus examination via fundus photography;Adverse Event Incidence Rate;Comfort Score;Optimal corrected vision;Ocular Surface Microbiota;Corneal Epithelial Defect Extent Grading;Intraocular pressure;Anterior Segment Examination and Anterior Segment Photography (Excluding the Corneal Epithelium); INCLUSION CRITERIA: 1. When signing the informed consent form, the subjects must be at least 18 years old and no more than 75 years old (inclusive of both boundaries). 2. At least 6 months prior to screening, the subjects must have a previous clinical diagnosis or complaint supporting dry eyes in both eyes. 3. Within 30 days before starting the washout period and before the visit 0, the subjects must have used artificial tears not permitted by the study protocol; and during the study period, they must agree to discontinue using artificial tears permitted by the study protocol. 4. The dryness score of both eyes is >= 50 (0‐100 VAS). 5. The study eyes must meet all of the following criteria: the corneal tCFS score is > 6 or the CFS score of any corneal sub‐region is >= 2.5; the Schirmer test result (without surface anesthesia) is >= 1/5 min. 6. The best corrected visual acuity (BCVA) of the study eyes is >= 4.3 (standard logarithmic visual acuity scale, 5‐point recording m