GSTM1 and Atrophy: By OCT, macular thinning (atrophy) was found significantly higher among children with Hb SS (9 out of 16 eyes; 56.3%, bilateral in 3 children and unilateral in 3 children) (Figure 2) and a child with Hb SC (unilateral in one eye; 16.7%) while no abnormalities were detected in children with Hb SB0 and Hb SB+.