Imbalance of macro- and microelements in the scleral shell of the eye in various forms of glaucoma

Abstract

PURPOSE. To conduct a comparative study of the balance of macro- and microelements in scleral biopsy samples taken from patients with various clinical forms of glaucoma.METHODS. The content of macro- and microelements was analyzed in scleral biopsy samples of 16 patients with primary open-angle glaucoma (POAG), 13 patients with normal tension glaucoma (NTG) and 15 patients with pseudoexfoliative glaucoma (PEG). The mean age of the patients was 79.5±2.5 years. For control, fragments of the sclera of 14 cadaveric eyes without a history of glaucoma were used. Concentration of macroelements — K, Mg, Ca, Fe — was determined by inductively coupled plasma atomic emission spectrometry, the level of microelements — Zn, Cu, Al, Mn — by inductively coupled plasma mass spectrometry.RESULTS. A statistically significant shift in the balance of Cu/Zn compared with controls was found in all forms of glaucoma: NTG (p=0.008), PEG (p=0.006), POAG (p=0.03); while no differences between NTG and POAG in this indicator were detected (p=0.609), with PEG the difference was significant (p=0.0001). The Cu/Fe ratio in the scleral samples of glaucomatous eyes also significantly differed from controls in both NTG (p=0.009) and PEG (p=0.006), as well as in POAG (p=0.006). This parameter in patients with POAG significantly differed from the corresponding parameter in the groups with NTG (p=0.0001) and PEG (p=0.016). A shift in the balance of Mn/Cu compared with controls was detected only in the sclera of patients with NTG (p=0.0064), there were no corresponding differences with controls in PEG (p=0.157) and POAG (p=0.773), but a significant difference was found between NTG and POAG groups (p=0.0001). The balance of Mn/Fe in comparison with the control group was disturbed in all forms of glaucoma: NTG (p=0.0066), PEG (p=0.00034), POAG (p=0.0027). At the same time, in patients with NTG and PEG, the balance of Mn/Fe differed significantly from this indicator in POAG (p=0.078 and p=0.0485, respectively). The most pronounced imbalance of Mg/Ca compared with controls was found in the sclera of patients with PEG (p=0.01) and POAG (p=0.0254).CONCLUSION. In all studied forms of glaucoma, disturbances in the ratios of Cu/Zn, Cu/Fe, Mn/Cu, Mn/Fe and Mg/Ca of varying severity in the sclera were revealed in comparison with the sclera of eyes without glaucoma. Differences in the indicated ratios between NTG, POAG and PEG have also been established, which may define the features in the pathogenesis and clinical course of these forms of glaucomatous lesions.