The study aims to compare the differences of ocular surface features in controls and patients with diabetes and dry eye syndrome, to thoroughly evaluate the ocular surface health of diabetics, and to find out the relationship between dry eye syndrome and diabetes

In this study, we perform a completely comparison of ocular surface characteristic including the Ocular Surface Disease Index (OSDI) questionnaire,tearfilm break up time(BUT),corneal fluorescein scores(CFS),Shirmer test,corneal sensitivity)among diabetic patients with DE, diabetic patients without DE, non-diabetic patients with DE and normal subjects and analysis of EGF, IL-17A, IL-1β, IL-8 and TNF-α in tears and their clinical correlations are also performed to investigate potential biomarkers for diagnosis of diabetic with DE.

Inclusion Criteria:

1. dry eye diagnosis according to Expert's Consensus About Clinical Diagnosis and Treatment（Corneal Disease Group of Ophthalmological Society, Chinese Medical Association）: ①OSDI≥13，②positive dry eye soigns(ST≤10mm/5min；BUT≤10s；CFS>0)
2. type 2 diabetes diagnosis according to American Diabetes Association：Standards of Medical Care in Diabetes -2017(ADA, American Diabetes Association)
3. Willing to sign the consent form.

Exclusion Criteria:

1. Having known Eye infection, allergy, malformation, abnormal eye movement
2. Exclusion of eye injury, any kind of eye surgery
3. Exclusion of other disease may cause neuropathy or influence tear producing
4. Using systematic or local antibiotics that may influence tear producing

Elimianation Criteria

1. poor compliance
2. voluntary withdrawal
3. any other kind of situation that researchers consider not suitable for further study.

Asian