Serum Markers of Oxidative Stress and Antioxidant Status in Keratoconus: Ischemia-Modified Albumin, Malondialdehyde, and Total Thiol Levels

Background and Objectives: Keratoconus (KC) is a progressive corneal ectatic disorder characterized by stromal thinning, irregular astigmatism, and visual impairment. Increasing evidence suggests that oxidative stress plays a significant role in the pathogenesis of KC. Biomarkers such as ischemia-modified albumin (IMA), malondialdehyde (MDA) and total thiol (TT) have been widely used to assess oxidative status. This study aims to evaluate the role of oxidative stress in KC disease by comparing serum levels of IMA, MDA, and TT between KC patients and healthy controls. Material and Methods: Forty patients diagnosed with KC and 43 healthy individuals of similar age and gender were included in the study. Patients with KC were classified in 4 stages according to the modified Krumeich KC classification system. IMA, MDA, and TT levels were compared in serum samples from patient and control groups. Results: Serum IMA levels were 2.52 ± 0.07 in the KC group and 1.2 ± 0.03 in the control group. The difference was statistically significant (p < 0.001). While serum MDA levels were 1.68 ± 0.05 in the KC group, they were 0.74 ± 0.04 in the control group. The difference was statistically significant (p < 0.001). Serum TT levels were 0.82 ± 0.41 in the KC group and 2.23 ± 0.04 in the control group. The difference was statistically significant (p < 0.001). Conclusions: Elevated serum IMA and MDA levels, together with decreased TT levels, in patients with KC are likely associated with increased oxidative stress. These parameters may serve as auxiliary biomarkers for evaluating disease pathophysiology and may represent potential targets for future diagnostic and therapeutic strategies.