Evaluate the efficacy and safety of ocular surface microbiota transplantation as an adjunctive therapy for dry eye, and explore its impact on the structure of the ocular surface microbiota.
Aged 18 to 70 years, male or female.
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.
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.
Parallel
Ocular surface microbiota transplantation
Biological/VaccineOcular surface microbiota transplantation
Placebo Group
Biological/VaccineFake transplant operation
Score on the Visual Analog Scale (VAS) for Ocular Discomfort
The severity of ocular discomfort (e.g., dryness, pain) is assessed using a 100-mm Visual Analog Scale (VAS). Participants mark their level of discomfort on a line from 0 mm ("no discomfort") to 100 mm ("worst imaginable discomfort"). The score is the distance measured in millimeters (mm). A higher score indicates more severe symptoms (worse outcome).
Corneal Fluorescein Staining Score (using the NEI scale)
Corneal epithelial damage is assessed by fluorescein staining and graded according to the National Eye Institute (NEI) scale. Each of the five corneal areas is scored from 0 (no staining) to 3 (severe confluent staining). The total score is the sum of all areas, ranging from 0 to 15. A higher score indicates more severe corneal damage (worse outcome).
Change in conjunctival sac microbiota composition assessed by 16S rRNA gene sequencing
Microbiota from conjunctival sac swab samples is analyzed using 16S rRNA gene sequencing. Key outcomes include: 1) Alpha diversity change (Shannon Index, unitless), where a higher index indicates greater microbial richness and evenness; 2) Beta diversity change (Weighted UniFrac distance, unitless), measuring compositional shifts between samples; and 3) Change in relative abundance (%) of specific bacterial taxa (e.g., \*Corynebacterium\*, \*Pseudomonas\*).
Result of Schirmer I Test (without anesthesia)
Tear production is measured by the Schirmer I test (without topical anesthesia). A standardized paper strip is placed in the lateral canthus for 5 minutes. The length of wetting is measured in millimeters (mm). A lower value indicates reduced tear secretion.
Tear Film Break-Up Time (TBUT)
Tear film stability is assessed by measuring the tear film break-up time (TBUT). After instillation of fluorescein, the time interval between the last complete blink and the first appearance of a dry spot on the cornea is recorded in seconds (s). A shorter time indicates greater tear film instability.
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