Importance: Lipid layer thickness (LLT) reflects the lipid components of tear film, but is affected by the mucocutaneous components. This study investigated the therapeutic effect of the treatments for aqueous-deficient dry eye (ADDE) on LLT.

Objective: To investigate the effect of ADDE and its treatments on LLT measurements by tear interferometry.

Design, Setting, and Participants: This prospective comparative interventional study included 152 eyes from 152 patients with ADDE.

Interventions: Participants were classified into four groups: control group (Group 1), 3% diquafosol group (Group 2), punctal plug insertion group (Group 3), and combined treatment group (Group 4).

Main Outcomes and Measures: Average LLT (LLTave) was measured using a LipiView® II tear interferometer at baseline and one month after treatments.

Inclusion Criteria:

1. presence of one or more subjective symptoms of DED, including eye dryness, foreign body sensation, irritation, burning, blurred vision, and pain.
2. tear meniscus height (TMH) of <200 µm for aqueous deficiency measured using Keratograph 5M® (Oculus Optikgeräte GmbH, Wetzlar, Germany).
3. evidence of corneal and/or conjunctival damage on slit-lamp biomicroscopy with fluorescein staining.

Exclusion Criteria:

1. acute and chronic ocular surface diseases that affect DED, including infection, allergy, and autoimmune disease, and that interfere with tear interferometric measurements, such as corneal opacity and pterygium, were excluded.

2. a history of the use of contact lens, known systemic diseases such as Sjögren's syndrome, Stevens-Johnson syndrome, and ocular graft-versus-host disease.

3. any medical/surgical history related to tear production and tear function except that in the study protocol were excluded.

4. Hypersecretory meibomian gland dysfunction (MGD)

   • When both eyes of a patient could be included, an eye with the lower TMH was selected.