Preliminary Clinical Study of the Effectiveness and Safety of Ocular Surface Microbiota Transplantation in the Treatment of Dry Eye Disease

Inclusion Criteria: * Dry Eye Patient Group: * Aged 18 to 70 years, male or female. * Meets the diagnostic criteria for moderate to severe mixed dry eye according to the Expert Consensus on Dry Eye (2020), including: * At least one subjective symptom (e.g., dryness, foreign body sensation, burning, fatigue, discomfort, redness, or vision fluctuation). * Fluorescein tear film break-up time (FBUT) ≤ 5 seconds. * Willing and able to actively cooperate with the prescribed course of standard dry eye medications and ocular surface microbiota transplantation therapy for the study duration. * Voluntarily agrees to participate and signs the informed consent form. * Healthy Donor Group: * A family member of a participating subject. * Aged 18 to 50 years. * Normal ocular surface structure and function, with no ocular diseases or related symptoms, and good visual function. Exclusion Criteria: * Dry Eye Patient Group: * History of systemic chronic diseases (e.g., uncontrolled diabetes, autoimmune disorders). * Current or past history of eyelid abnormalities, conjunctival disease, or lacrimal duct obstruction. * History of any ocular surgery or regular wear of corneal contact lenses. * Active infection in the eye(s) or any other part of the body. * History of multiple episodes of viral keratitis or presence of significant neurotrophic keratitis. * Any other condition deemed by the investigator to be unsuitable for participation. * Healthy Donor Group: * Known infectious diseases (e.g., HIV, Hepatitis B). * Signs or symptoms suggestive of active ocular surface infection or other viral infections. * Current or past history of eyelid, conjunctival, or lacrimal duct diseases. * Use of systemic medications (including antibiotics), traditional Chinese herbal medicine, or probiotic supplements within 1 month prior to screening. * Pregnancy, lactation, or any other condition that may potentially affect the study outcomes.