DE scoring system (DESS)
blurred vision, fatigue, abnormal excessive blinking, gritty/sandy sensation, ocular itching/burning
To assess the symptoms related to DE, this questionnaire was used. DESS asked about the presence of 6 items: eye fatigue, ocular itching/burning, local redness, gritty/sandy sensation, blurred vision, and abnormal excessive blinking. Every item is represented with an answer of zero (absent), one (sometimes), two (frequent), and 3 (always found). The score of DESS ranged from zero (minimal score) to 18 (maximal severe score) [