Scleral strengthening treatment and its effect on the eyeball coats oxidative stress in progressive myopia

In patients with progressive myopia, there is an imbalance between the processes of lipid peroxidation and antioxidant protection, which is confirmed by changes in the level of hypoxia markers and the activity of the antioxidant enzyme superoxide dismutase (SOD) in the tear fluid (TF). Purpose: to study the SOD activity in the TF of patients with moderate and high progressive myopia after sclera-strengthening treatment. Material and methods. We examined 82 patients (82 eyes) aged 8 to 17 years with progressive myopia (ave 9.1 ± 0.3 D), divided into two main groups: in the 1st group (47 patients), minimally invasive scleroplasty (MIS) was performed using a biologically active graft, in the 2nd group (35 patients) — bandaging scleroplasty (BSP) according to the Snyder-Thompson technique using homoscleral graft. The control group consisted of 12 unoperated patients aged 7–13 years with low hyperopia (0.25 D to 1 D). At various times after MIS and BSP, SOD activity (by inhibition of quercetin autoxidation) and total protein concentration according to Lowry were determined. Results. SOD activity in the TF before surgery in patients of group 1 (32.0 ± 5.3 U/mg protein) and group 2 (24.7 ± 6.4 U/mg protein) was in generally significantly higher than in the control group (20.0 ± 3.2 U/mg protein). At the same time, in some patients with initially low SOD values, enzyme activity significantly increased 1 month after surgery (p < 0.01) and exceeded the control level by 4.3–5.2 times. In case of initially elevated SOD activity, on the contrary, the enzyme concentration significantly decreased (p < 0.01) — 3.5 times with BSP and 1.9 times with MIS. After 6 months, in patients of the MIS group with the initial level of SOD activity below the norm, the enzyme activity remained 2 times higher than normal values (p < 0.01). All other patients showed a decrease in SOD values to the control level, and in some cases below it. Conclusion. Sclero-strengthening treatment has a normalizing effect on SOD activity in the TF, which contributes to the correction of metabolic disorders caused by progressive myopia and confirms the importance of scleroplasty as a method activating bioregulation and normalizing oxidation-reduction processes in the eye tissues.