To explore the law of changes in ocular surface inflammation when 0.05% cyclosporine eye drops (II) is used to treat dry eye, 50 cases of mild to moderate dry eyes were included. The expectation is finding out whether cyclosporine has a regulatory effect on conjunctival microvascular parameters and other inflammation indicators after cyclosporine eye drops treat dry eye, and analyze the value of conjunctival microvascular indicators in dry eye immunosuppressive therapy.

Dry eye is a common ocular surface disease that affects people's visual function and quality of life. In recent years, with the changes of lifestyles, the prevalence of dry eye is gradually increased. According to the consensus definition of Chinese dry eye experts in 2020, dry eye is a chronic ocular surface disease caused by multiple factors, while inflammation is emphasized as an important role in the occurrence and development of dry eye. Therefore, in addition to use artificial tears to alleviate the symptoms of dry eye, it is clinically recommended to combine low-concentration ocular surface hormones or immunosuppressant for anti-inflammatory therapy. As an immunosuppressant, cyclosporine can inhibit the infiltration of CD4+ T cells on the ocular surface, inhibit the apoptosis of conjunctival goblet and lacrimal gland acinar cells, and effectively alleviate ocular surface inflammation. In addition, cyclosporine can inhibit the calcineurin pathway by forming an intracellular complex with cyclophilin, promote the production of tears, and increase the density of goblet cells. Cyclosporine has an impact on many molecules in the immune pathway of dry eye.

However, how to use and adjust immunosuppressant according to the ocular surface inflammation still depends on the subjective experience of doctors, and there is no uniform standard. Therefore, finding biological reference indicators for ocular surface inflammation is the key to promoting the standardization and precision of anti-inflammatory drugs. The stimulation of inflammation factors can lead to the expansion of the capillary network, thus, the function of ocular surface capillaries can be used as an important indicator of ocular surface inflammation. Now, the intelligent analysis technology based on ocular surface micro vessels owned by my research team can clearly obtain blood flow imagines and topographic maps of blood vessel distribution in conjunctival micro vessels, and quantify the changes in microvascular shape, density and complexity, which is a kind of non-contact and convenient evaluation method. In our previous studies, it was confirmed that the treatment of moderate to severe dry eye with low concentrations of ocular surface hormones can cause changes of ocular surface microvascular parameters. Investigators hope to further observe the temporal and spatial changes of ocular surface microvascular function during the treatment of dry eye with cyclosporine, and correlation with inflammatory cells, inflammatory factors and neuroinflammation, explore the effect of the drug on dry eye related inflammation target issues and the guiding value of conjunctival microvascular indicators in dry eye immunosuppressive therapy, in order to change the previous dry eye anti-inflammatory treatment and the mode of medication based on the doctor's personal experience.

Inclusion Criteria:

• 18-65 years old;
• meet the 2-3 grade dry eye diagnosis: 1) At least one eye has one or more ocular discomfort symptoms and OSDI score ≥23; 2) At least one eye meets one of the following two: 2 mm/5min≤Schirmer I test (no anesthesia) <10 mm/5min; BUT≤10s. 3) Corneal spotting but no extensive erosion.

Exclusion Criteria:

• Contact lens wearers;
• Allergies to the study drug;
• Active eye infections; history of serious systemic diseases;
• Pregnancy or breastfeeding;
• Receiving or starting other treatments that may interfere with the interpretation of the results;
• Participating any other clinical trials within 3 months;
• Previous eye surgery, including laser treatment and refractive surgery;
• Need or have undergone punctal embolization or nasolacrimal duct obstruction;
• KCS secondary to the destruction of conjunctival goblet cells (such as vitamin A deficiency) ;
• Scar formation (such as cicatricial pemphigus, alkali burn, trachoma or radiation).