Beta-thalassemia major, a genetic blood disorder, can lead to thinning of the retinal nerve fiber layer (RNFL). A study compared RNFL thickness in 56 patients with beta-thalassemia major and 64 healthy individuals. The results showed that the RNFL was significantly thinner in beta-thalassemia major cases compared to healthy controls. Thinner RNFL was associated with longer duration of the disease and use of iron chelation therapy.