Eye Dryness Evaluation in Primary Sjögren's Syndrome

All clinical trials evaluating the efficacy of immunomodulatory drugs in pSS are negative. This could be due to a lack of sensitivity of the outcome measures used so far to define the response. In this study, investigator will evaluate the feasability, tolerability, and performance of new tools to assess disease evolution: * investigator will develop a webapp to measure the intensity of the symptoms at home on a daily basis (ecological assessment) * investigator will evaluate new ophthalmologic procedures, already used in other conditions but never in pSS, which assess the severity of eye involvement in the disease * investigator will develop an automated method to score the severity of ocular surface lesions in the disease. Patients with a diagnosis of pSS will be included in the study, will undergo detailed ophtalmologic examination, and will then use a webapp, installed on their smartphone, to score their symptoms everyday during 3 months.