Ocular surface temperature of a normal person is around 34.6 degree centigrade. After instilling the eye drop, depending on the temperature of the eye drop and the ocular surface, the ocular surface temperature will temporally increase or decrease sightly. Warm feeling will make blood vessels dilated and more blood will pass through to bring more blood flow out of our body to the heated area of the body and makes cells more permeable. Therefore, heating the ocular surface with heated eye mask after instilling artificial tears has the possibility to improve drug permeability on the ocular surface.

Evaporative dry eye (EDE) is common and can lead to ocular pain, decreased visual quality, and reduced quality of life. 3% diquafosol (DQS) ophthalmic solution and heated eye mask (HEM) have been found to be beneficial in reducing signs and symptoms of dry eye. Warm compress therapy temperature of 40 °C to 45 °C have been typically advocated to melt the meibium causing obstruction at the orifices of the meibomian gland, eventually allowing increased lipid layer of the tear film. While in impact of heat on the ocular surface (OS) has not been extensively studied. Controlled and precise application of heat has the ability to create a cascade of events in the skin and thus aids in facilitating a faster movement of molecules into and across the skin. Possible mechanisms of enhancing drug permeation include on the ocular surface could be: (mechanisms may operate individually or concurrently):

• increase in drug diffusivity in the vehicle and/or in the ocular surface
• increase in partitioning and diffusion
• alteration in the lipid structure
• increased local blood flow Therefore, the purpose of this RCT is to assess the impact of instilling 3% DQS ophthalmic solution follow by HEM raising the OS temperature by 40 degrees centigrade for 10 minutes.

Inclusion Criteria:

• Age ≥18 years
• The presence of at most one symptom including burning, foreign body sensation, itching or eye fatigue for 3 months
• OSDI score ≥ 13 and TBUT <5 s or NIBUT < 10s
• Able and willing to comply with the treatment/follow-up schedule

Exclusion Criteria:

• A recent history (past 30 days) of topical ophthalmic medication use, including antibiotics, steroids, non-steroidal anti-inflammatory drugs, or required the chronic use of topical ophthalmic medications
• Eyelids or intraocular tumors that should not put pressure
• Active allergy or infection or inflammatory disease that may have prevented the subjects from completing the study at the ocular surface
• Any structural change in lacrimal passage
• Glaucoma
• Diabetes or other systemic, dermatologic, or neurologic diseases that affect the health of ocular surface
• Use of any systemic anti-inflammatory drugs or medication that may interfere with tear production, such as antianxiety, antidepressive, and antihistamine medications within 3 months

The study's findings will be shared regardless of the effect's direction. All possible beneficiaries of the research, including patients, carers, family, doctors, advisory boards, and medical boards, will receive trial data. Publications in high impact, open-access medical journals and talks at national and international medical conferences will serve this purpose.

The Steering Committee will write and submit the report for publication at the end of the study

Use in clinical studies

Masked examiner for all clinical assessments will not involved in the data collection or group allocation procedure for this research. The investigator will not be aware of the three groups.