Inclusion Criteria:
- Subjects must meet all the following criteria to be eligible:
- Healthy, aged 18-50 (inclusive), all genders.
- Signed informed consent pre-screening; comprehension of study and ability to complete it per protocol.
- BMI 19-27 kg/m² (inclusive); ≥45 kg for females, ≥50 kg for males.
- Bilateral best-corrected visual acuity ≥4.7 (5m, 5-point logMAR).
- No reported eye discomfort/abnormalities 1 month before randomization.
- No history of dry eye disease, as assessed by the investigator.
- No history of ocular inflammation (e.g., allergic conjunctivitis, uveitis) per investigator judgment.
- Use effective contraception during study and 30 days post-last dose:
Females: non-pregnant, non-lactating; premenopausal use approved methods, no egg donation.
Males with fertile partners: vasectomy (≥30 days, no viable sperm) or approved contraception, no sperm donation.
- Non-smoker, remain smoke-free during study.
- No excessive alcohol (>14 units/week) or illicit drug use history; abstain from both during study.
Exclusion Criteria:
- Subjects will be excluded if they meet any of the following:
- History or current diseases/conditions (e.g., circulatory, endocrine disorders) that pose risks or interfere with the study, as judged by the investigator.
- Blood donation or loss >300 mL within 56 days before randomization; no blood donation during the study.
- Allergy to study medications (e.g., lifitegrast, excipients).
- Prior participation in non - placebo lifitegrast clinical trials.
- Clinically significant abnormal test results:
Vital signs: ear temp >37.7℃ or <35.4℃; pulse >100 or <60 bpm; systolic BP ≥150 or <90 mmHg; diastolic BP ≥90 or <50 mmHg.
ECG: QTcF ≥450 ms (male), ≥460 ms (female). Lab tests: abnormal blood/urine, coagulation, infectious markers, drug/alcohol screenings.
Abnormal abdominal ultrasound or eye exams.
- Intraocular/laser eye surgery within 12 months, other eye surgeries within 3 months before screening, or planned eye surgery during the study.
- Use of ophthalmic drugs (incl. artificial tears), anticholinergics, oral/nasal steroids within 1 month before screening or during the study.
- Tobacco/nicotine use within 6 months before randomization.
- Contact lens use within 1 month before randomization or during the study.
- Prescription/OTC/herbal medications within 2 weeks or 5 half - lives (longer) before randomization or during the study.
- Pregnancy, lactation, or positive pregnancy test at screening.
- Participation in drug/device trials within 30 days or 5 half - lives (longer) before screening, or planned participation during the study affecting results.
- Conditions increasing risks, affecting compliance, or deemed unsuitable by the investigator (e.g., needle phobia).