Evaluation and comparison of the indices of systemic oxidative stress among black-Africans with age-related cataracts or primary glaucoma

Abstract

Purpose:Oxidative stress has been implicated in the pathophysiology of glaucoma, cataract, and many degenerative diseases. The purpose of this study is to evaluate the systemic oxidative stress in black-African patients diagnosed with primary glaucoma or age-related cataract (ARC) and compare these indices to normal control patients and between the two conditions.Methods:This was a descriptive cross-sectional study of consecutive recruited subjects attending a tertiary care facility. One hundred adults were enrolled and sub-grouped into: Normal controls (n = 20), patients with primary glaucoma (n = 40), and patients with cataract (n = 40). The data were collected on patient demographics and clinical information. Ten milliliters of the venous blood was taken from each subject for the evaluation of serum biochemical indices of oxidative stress. Laboratory measurements of enzymatic and nonenzymic anti-oxidants, as well as lipid peroxidation, were conducted using established and validated spectrophotometric methods. The systemic oxidative stress was measured by the serum levels of anti-oxidant enzymes and lipid peroxidation, and compared between the groups and to a control group of patients.Results:Statistically, significantly reduced serum levels of glutathione, glutathione-S-transferase, superoxide dismutase, catalase, and ascorbic acid were found in the patients with glaucoma or cataract when compared with controls (P < 0.05 for all). Differences in serum lipid peroxidation levels across or between the groups were nonsignificant. Serum protein levels were significantly higher among the subjects with cataract or glaucoma than in controls.Conclusion:Our results concur with findings in Caucasian study cohorts. This indicates that in black-Africans, primary glaucoma, and ARC are associated with increased systemic oxidative stress. This supports the existing evidence on the role of oxidative stress in these ocular disorders and reinforces the rationale for the use of anti-oxidants in the management and possible prevention of these conditions.

Oxidative and Anti-Oxidative Stress Markers in Chronic Glaucoma: A Systematic Review and Meta-Analysis

“…The assessment of the quality of the 22 studies that were included was performed using the STROBE criteria, with the results varying from 68.8 [45] to 90.6% [32,46], with a mean score of 80.3±6.3. Overall, the studies performed best in the methods section and worst in the discussion section.…”

“…Levels of oxidant or antioxidant markers were evaluated in serum in 12 studies [27,28,29,31,32,34,35,39,40,43,45,48], in aqueous humor in six studies [30,36,37,38,44,47], or both in three studies [33,41,42]. One study measured the markers in blood hemolysate [46].…”

“…The markers were measured in different types of glaucoma: only in primary open angle glaucoma (POAG) [29,30,36,37,39,41,43,44,45,46,48], only in primary angle closure glaucoma (PACG) [27,31], only in pseudoexfoliation glaucoma (PEG) [28,32,33], in both POAG and PACG [38], in both POAG and PEG [35,42,47], in both POAG, PACG and PEG [40], or it was not specified [34]. Inclusion criteria for glaucoma patients were similar for most studies [27–33,35–39,41,43,46,47].…”

“…Some studies required an elevation of the intraocular pressure for glaucoma patients [27,28,32,33,35,37,38,43,48]. Criteria for glaucoma were not defined in five studies [34,40,42,44,45]. …”

“…Eight studies excluded patients on special diets with antioxidant vitamins such as vitamin C and E [32,37,38,41,43,44,47,48]. Patients with previous intraocular surgery were excluded in eight studies [31,36,37,39,45,46,47,48]. …”