Purpose The early revealing of the antioxidant system disorders in myopic patients is extremely important for correction and prevention of dystrophic changes in retina and sclera of the eye. One of the most powerful intracellular antioxidants is glutathione (S.M. Cohen, 1994; Paula S. Samiec, 1998). Connected SH and S‐S – groups represent tiol and disulfide bonds in protein structures. As a whole concentration levels of these groups can be considered now as important link of antioxidant protection. To evaluate the protective antioxidant system in patients with myopia by the concentration levels of free and connected SH and S‐S – groups in tear liquid in patients with myopia of different degree the work was conducted. Methods 34 children aged 8 ‐ 14 years with myopia of different degree and control group of the same age (10) were examined. Except ophthalmologic observations free and connected SH and S‐S – groups in tear liquid were defined by spectrocolormeter Spekol‐210 wave length 356 nm and 412 nm accordingly. Results It was established that levels of connected SH and S‐S – groups in tear liquid had tendency to increase in average on (4, 8 – 14, 5) % in dependence of myopic degree. Free SH‐ groups content in tear of children with high myopia was lower in comparison with control group on 28% (54,2 ± 5,5) u., P<0,05. Conclusion Free SH‐ groups content in tear of children with high myopia was significantly lower than in children of other groups. It confirmed that protective antioxidant system abilities are weakened in myopia and that they decrease with myopic severity.