The authors focus on the assessment of ocular manifestation in patients with primary Sjögren's syndrome using the Ocular Staining Score. The method offers the possibility to stain different ocular structures separately: cornea with fluorescein and conjunctiva with lissamine green dye and provides for separate evaluation of abnormalities, unlike the current system assessing ocular damage where ocular tissues are stained either with bengal rose or lissamine green dye. The paper presents new criteria for the diagnosis of dry eye secondary to the autoimmune Sjögren's syndrome and their high specificity (94.7% and 93.3%)ö based on the results of clinical trials in 1618 patients, conducted by an international research team.