The objective of the study is to compare the efficacy and safety of different hyaluronic acid tear substitutes formulations in patients with evaporative dry eye. For this purpose, a randomized, single-blind clinical trial has been designed.

Inclusion Criteria:

1. Self-reported history DED.
2. Ocular surface disease index (OSDI) > 13 points.
3. Non-invasive tear film break-up time (NIBUT) < 10 s.
4. Schirmer test (ST) without anesthesia ≥ 5 mm.
5. MGD grade > 1. For MGD, the Sirius device (CSO, Florence, Italy) was used, which determines MGD grade based on loss area of meibomian glands (LAMG). MGD grade was scored from 0 to 4 (MGD grade 1 = LAMG < 25%; MGD grade 2 = LAMG ≥ 25% and < 50%; MGD grade 3 = LAMG ≥ 50% and < 75%; MGD grade 4 = LAMG ≥ 75%).

Exclusion Criteria:

1. Abnormal lid anatomy, including active blepharitis, and active lid margin.
2. All corneal disorders that affect diagnostic test, such as active corneal infection and corneal dystrophies.
3. Active ocular allergies.
4. Vectored thermal pulsation (VTP) intense pulse light (IPL), quantum molecular resonance (QMR), or other procedure to treat DED within the previous 6 months.
5. Intraocular surgery or laser ocular surgery within the previous 6 months.
6. Use of topical antibiotics and anti-inflammatory treatments, including steroids and non-steroidal anti-inflammatory drugs.
7. Systemic autoimmune diseases.
8. Contact lens wearers.
9. Pregnant or lactating women.
10. Patients who did not understand or comprehend the informed consent.

0.20% Cross-linked hyaluronic acid tear substitute and 0.15% hyaluronic acid tear substitute are transparent, with no special smell and the bottles were identical in appearance such that patients, investigators and care provider were masked to treatment assignment.