IL1B and diabetic retinopathy: Vitreous levels of IL-1β are elevated in retinitis pigmentosa (N. Yoshida et al., 2013a), and increased IL-1β levels are found in the serum (Demircan et al., 2006), vitreous (Demircan et al., 2006; Zhou et al., 2012), and aqueous humour (Wu et al., 2017) of patients with diabetic retinopathy.