A new objective method to diagnose and classify dry eye patients has been carried out in this study. Tear film quality was objectively evaluated by means of a double-pass system in patients with healthy eyes, with some tear deficiency and dry eye patients. Intraocular scattering present in those eyes was studied by analyzing a new parameter called Objective Scatter Index (OSI) obtained with the Optical Quality Analysis System (OQAS), a device based on the double-pass technique. Several complementary subjective clinical exams commonly used to evaluate tear film quality were also performed on patients (dry eye questionnaire, Non-Invasive Break-Up Time (NIBUT), Phenol Red Thread Test and Visual Acuity) in order to correlate them with the OSI parameter. Correlations between OSI and dry eye questionnaire and NIBUT showed that there exists a trend that could help to classify more accurately patients affected by some tear problem