Introduction. Arterial hypertension (HTN) is one of the leading public health problems, causing a challenging and complex visual impairment known as hypertensive retinopathy (HR). Its pathogenesis is caused not only by changes in retinal homeostasis because of high blood pressure (BP) but, undoubtedly, other pathological mechanisms are involved, including oxidative stress (OS).
The aim of the study was to evaluate the serum and tears total antioxidant capacity (TAC), as a single parameter of oxidative stress associated with the development of HR and to establish whether there is a correlation between its level and the grade of HR.
Materials and methods. 90 hypertensive patients divided according to the Keith-Wagner-Barker grading system of HR into three groups: GI – 36 patients; GII – 35 patients; GIII – 19 patients. TAC in tears and serum was measured and the obtained results were analysed by Kruskal-Wallis and Mann-Whitney tests in SPSS Statistics. The Spearman correlation coefficient was determined. A p≤0.05 was considered statistically significant.
Results. TAC values in the tears samples of hypertensive patients increased statistically significant as HR advanced in grade (p=0.003). Serum level of TAC showed only a tendency of decrease (p=0.182). Only tears TAC levels correlate significantly with low power with HR degree (r=0.357**, p=0.001). Serum and tears levels of TAC have a statistically significant negative low power correlated with each other (r= – 0.226*, p=0.032).
Conclusions. The continuous rise in TAC levels in tears along with HR progression is a possible mechanism by which the eye copes with the damaging reactive oxygen species produced by OS. The increase in TAC may partially explain the gradual and delayed development of retinopathy stages in HTN.
Keywords: hypertensive retinopathy, total antioxidant capacity, oxidative stress.
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